Abstract
Background
In 2007, caesarean deliveries comprised 28% of all hospital deliveries in Ontario. Provincial caesarean delivery rates increased with maternal age and varied by Local Health Integration Network. However, the accepted rate of caesarean delivery in a low-risk maternal population remains unclear.
Objectives
To review the literature to assess factors that affect the likelihood of experiencing a caesarean delivery, and to examine Ontario caesarean delivery rates to determine whether there is rate variation across the province.
Data Sources
Data sources included publications from OVID MEDLINE, OVID MEDLINE In-Process and Other Non-Indexed Citations, OVID Embase, EBSCO Cumulative Index to Nursing & Allied Health Literature (CINAHL), and EBM Reviews, as well as data from the Canadian Institute for Health Information Discharge Abstracts Database and the Better Outcomes and Registry Network.
Review Methods
A mixed-methods approach was used, which included a systematic review of the literature to delineate factors associated with the likelihood of caesarean delivery and an analysis of administrative and clinical data on hospital deliveries in Ontario to determine provincial caesarean delivery rates, variation in rates, and reasons for variation.
Results
Fourteen systematic reviews assessed 14 factors affecting the likelihood of caesarean delivery; 7 factors were associated with an increased likelihood of caesarean delivery, and 2 factors were associated with a decreased likelihood. Five factors had no influence. One factor provided moderate-quality evidence supporting elective induction policies in low-risk women. The overall Ontario caesarean delivery rate in a very-low-risk population was 17%, but varied significantly across Ontario hospitals.
Limitations
The literature review included a 5–year period and used only systematic reviews. The determination of Robson class for women is based on care received in hospital only, and the low-risk population may have included data from women with obstetrical conditions that warranted a caesarean delivery.
Conclusions
There is moderate-quality evidence that—compared with expectant management—an induction policy is associated with a decrease in caesarean delivery rates in low-risk women. There is significant caesarean delivery rate variation among Ontario hospitals.
PLAIN LANGUAGE SUMMARY
A caesarean delivery is a surgical procedure to deliver 1 or more babies. It can be done when a vaginal delivery would be risky for the mother or baby. There are concerns that the mother and/or the baby may have serious complications from a caesarean delivery. It is important to know what factors increase the chance of having a caesarean delivery. It is also important to know how many caesarean deliveries are done in Ontario. This review found 14 factors, of which 9 were associated with either an increased or decreased chance of having a caesarean delivery. Of these, a policy of inducing labour lowered the rate of having a caesarean delivery compared with a policy of expectant management in low-risk women. An analysis of a registry for Ontario hospital births found a caesarean delivery rate of about 17% among women at very-low risk for complications. This rate varies among Ontario hospitals.
BACKGROUND
Objective of Analysis
The objective of this analysis was to review the literature to assess factors that affect the likelihood of experiencing a caesarean delivery, and to examine Ontario caesarean delivery rates to determine whether there is rate variation across the province.
Clinical Need and Target Population
A caesarean delivery is a surgical procedure to deliver 1 or more babies. In most cases, a caesarean delivery is performed when a vaginal delivery would put the baby's or mother's life or health at risk.
Accepted indications for caesarean delivery include but are not limited to difficult or non-progressing labour, breech or other abnormal fetal position or size, non-reassuring fetal heart rate, and/or previous caesarean delivery, (1;2) but the benefits of a caesarean delivery compared with a vaginal delivery for a low-risk population continues to be debated. (3) In 2008, the Society of Obstetricians and Gynaecologists of Canada and other related Canadian professional organizations released a joint policy statement advocating for normal childbirth in a low-risk population. (4) According to these recommendations, as well as guidelines from the American (1) and British medical organizations, (5) caesarean deliveries should be offered only when vaginal delivery poses an increased risk to either the mother or the baby. These guidelines lack specificity, however, due to debate around indications for caesarean deliveries and appropriate rates at the population level. The accepted rate of caesarean delivery in a low-risk maternal population remains unclear.
Maternal, infant, and obstetrical factors have all been cited as affecting the likelihood of having a caesarean delivery. (6) Maternal factors may include but are not limited to age, pre-existing health conditions (such as diabetes), obesity, hypertension, previous caesarean delivery, pregnancy-related health conditions (including gestational diabetes), pre-eclampsia, eclampsia, and maternal preference. Infant factors include antenatal problems preceding the intrapartum period (such as fetal anomalies and/or intrauterine growth restriction), and suspected macrosomia, malposition, or multiple births. Obstetrical factors are conditions brought about by the presence of the current intrauterine pregnancy, such as placental abruption, placenta accreta, placenta previa, prolapsed cord, and non-reassuring fetal heart tracing.
Technology/Technique
Rates of caesarean delivery as a percentage of all live births have increased in all Organisation for Economic Co-operation and Development (OECD) countries in recent decades. (7;8) Caesarean delivery rates now exceed 30% in several industrialized countries, including Canada, the United States, and Australia. (7;8) Studies have reported concerns about increased maternal and infant mortality after caesarean delivery, as well as maternal morbidity in deliveries subsequent to the primary caesarean procedure. (3;9) These concerns, combined with the greater financial cost of a caesarean birth, (10;11) raise the challenging question of the appropriate rate for caesarean delivery. The World Health Organization (WHO) has proposed a rate guideline of 10% to 15% for low-risk, singleton, vertex, full-term pregnancies, and the United States Public Service has proposed a guideline of 10.5%, (7) but these have been criticized for not adjusting for changing obstetrical practices and attitudes among both health care providers and patients. Reflecting these issues, the U.S. Healthy People 2020 initiative revised its recommended rates from 15% of all births in 2000 to a new target of 23.9% among nulliparous, singleton, vertex, full-term pregnancies with no previous caesarean delivery; this is a 10% decrease from the 2007 baseline rate of 26.5%. (12)
Impact on the System
Of every $10 (Cdn) spent on inpatient care in Canada, $1 (Cdn) is spent on childbirth and newborn care. (11) Compared to vaginal births, caesarean deliveries cost hospitals twice as much in obstetrical care for both mothers and babies. (11) The average hospital inpatient cost per delivery for typical patients is $4,930 (Cdn), and national estimates suggest that a primary caesarean delivery costs approximately $2,265 (Cdn) more than a typical vaginal delivery with no other interventions. (11) In 2008/2009, the total costs for all primary caesarean hospitalizations were estimated to be $292 million (Cdn). (11) However, health care providers are currently operating without an agreed-upon benchmark for caesarean delivery rates. Manitoba has the lowest primary caesarean delivery rate among the provinces, at 14% of all deliveries in 2008/2009. (11)
Global Rates and Trends
Across OECD countries, caesarean delivery rates increased from 14% of all births in 1990 to nearly 26% in 2009. (10) Rates were highest in Turkey and Mexico, at over 40% of all deliveries, and lowest in the Netherlands (14%) and Nordic countries (including Finland, Iceland, Norway, and Sweden). In the Netherlands, home births are a common option for women with low-risk pregnancies; 30% of all births occurred at home in 2004. (13)
The observed increase in caesarean delivery rates temporarily slowed during the 1990s in some OECD countries such as Canada and the United States as a result of changes in obstetrical practice, including a trial of normal labour and delivery after previous caesarean delivery to reduce the number of repeat procedures. (14) However, caesarean rates soon increased, in part due to reports of complications from trial of labour and continued changes in patient preferences. (15) Other trends, such as increases in first births among older women and the rise in multiple births resulting from assisted reproductive therapy, also contributed to the global increase in caesarean deliveries.
Rate increases since 2000 have been particularly rapid in Denmark, the Czech Republic, Poland, and the Slovak Republic. (10) Finland and Iceland are the only 2 OECD countries that have slightly reversed the trend of rising caesarean delivery rates since 2000. (10) The continued rise in caesarean deliveries is only partly related to changes in medical indications. A recent study of caesarean delivery rates found that even after adjusting for maternal and medical factors, women who had a preference for a caesarean delivery were almost twice as likely to have one compared with women who preferred a vaginal delivery. (16)
Canadian Rates and Trends
Caesarean rates have increased steadily in Canada since 1995, stabilizing in the last decade, (17) but they vary substantially from region to region. In 2008/2009, primary (first delivery) caesarean rates ranged from 23% of deliveries in Newfoundland and Labrador to 5% in Nunavut. (11) As noted above, Manitoba had the lowest provincial rate, at 14%. (11)
Ontario Rates and Trends
In 2007, caesarean deliveries comprised 28% of all hospital deliveries in Ontario. (18) Among women who had full-term, singleton, vertex presentations, 23% had caesarean deliveries.
Provincial caesarean delivery rates increased with maternal age and varied by local health integration network (LHIN), but did not vary by neighbourhood income or neighbourhood educational attainment of the mother.
EVIDENCE-BASED ANALYSIS
Research Questions
This report addressed 3 research questions:
What are the factors affecting the likelihood of having a caesarean delivery in a low-risk obstetrical population?
What is the Ontario provincial caesarean delivery rate for a low-risk obstetrical population, and does this rate vary within the province?
What are the likely reasons for caesarean delivery rate variation in Ontario, if it exists?
Research Methods
A mixed-methods approach was used, which included a systematic review of the literature to delineate factors associated with the likelihood of caesarean delivery. Then, an analysis of administrative and clinical data on hospital deliveries in Ontario was used to determine provincial caesarean delivery rates, variation in rates, and reasons for variation. Details of each methodology are reported in their respective sections.
Expert Panel
In January 2013, an Expert Advisory Panel on Caesarean Delivery Rate Review was struck. Members of the panel included physicians, nurses, midwives, childbirth educators, obstetrical anesthetists, hospital administrators, and personnel from the Ministry of Health and Long-Term Care.
The role of the Expert Advisory Panel on Caesarean Delivery Rate Review was to contextualize the evidence produced by Health Quality Ontario and provide advice on the relevant issues pertaining to caesarean delivery rates in Ontario. However, the statements, conclusions, and views expressed in this report do not necessarily represent the views of Expert Advisory Panel members.
Systematic Review
Research Methods
Literature Search
Search Strategy
A literature search was performed on February 4, 2013, using OVID MEDLINE, OVID MEDLINE In-Process and Other Non-Indexed Citations, OVID Embase, EBSCO Cumulative Index to Nursing & Allied Health Literature (CINAHL), and EBM Reviews for studies published from January 1, 2008, to February 4, 2013. (Appendix 1 provides details of the search strategies.) Abstracts were reviewed by a single reviewer and, for those studies meeting the eligibility criteria, full-text articles were obtained. Reference lists were also examined for any additional relevant studies not identified through the search.
Inclusion Criteria
English-language full-text publications
published between January 1, 2008, and February 4, 2013
systematic reviews with meta-analysis of randomized controlled trials (RCTs) and/or observational data
maternal, obstetrical, fetal, or service-delivery factors
comparator was accepted routine care or no treatment
low-risk population
When more than 1 systematic review for a particular factor met the inclusion criteria, the most current review (i.e., the one with the most up-to-date literature search) was included.
Exclusion Criteria
individual observational studies or RCTs
comparisons of different techniques for a given intervention (i.e., early versus late administration of epidural)
systematic reviews whose body of evidence was included in an updated systematic review answering the same research question
Outcomes of Interest
caesarean delivery or preference for caesarean delivery
Quality of Evidence
The Assessment of Multiple Systematic Reviews (AMSTAR) measurement tool was used to assess the methodological quality of systematic reviews. (19)
The quality of the body of evidence for each outcome was examined according to the Grading of Recommendations Assessment, Development, and Evaluation (GRADE) Working Group criteria. (20) The overall quality was determined to be high, moderate, low, or very low using a step-wise, structural methodology.
Study design was the first consideration; the starting assumption was that RCTs are high quality, whereas observational studies are low quality. Five additional factors—risk of bias, inconsistency, indirectness, imprecision, and publication bias—were then taken into account. Limitations in these areas resulted in downgrading the quality of evidence. Finally, 3 main factors that may raise the quality of evidence were considered: the large magnitude of effect, the dose response gradient, and any residual confounding factors. (20) For more detailed information, please refer to the latest series of GRADE articles. (20)
As stated by the GRADE Working Group, the final quality score can be interpreted using the following definitions:
| High | High confidence in the effect estimate—the true effect lies close to the estimate of the effect |
| Moderate | Moderate confidence in the effect estimate—the true effect is likely to be close to the estimate of the effect, but may be substantially different |
| Low | Low confidence in the effect estimate—the true effect may be substantially different from the estimate of the effect |
| Very Low | Very low confidence in the effect estimate—the true effect is likely to be substantially different from the estimate of effect |
Results of Systematic Review
The database search yielded 352 citations published between January 1, 2008, and February 4, 2013 (with duplicates removed). Articles were excluded based on information in the title and abstract. The full texts of potentially relevant articles were obtained for further assessment. Figure 1 shows the breakdown of when and for what reason citations were excluded from the analysis.
Figure 1: Citation Flow Chart.
Fourteen systematic reviews met the inclusion criteria. (21–34) The reference lists of the included studies were hand-searched to identify other relevant studies, but no additional citations were included.
For each included study, the study design was identified and is summarized below in Table 1, a modified version of a hierarchy of study design by Goodman. (35)
Table 1:
Body of Evidence Examined According to Study Design
| Study Design | Number of Eligible Studies |
|---|---|
| RCTs | |
| Systematic review of RCTs | 14 |
| Large RCT | |
| Small RCT | |
| Observational Studies | |
| Systematic review of non-RCTs with contemporaneous controls | |
| Non-RCT with non-contemporaneous controls | |
| Systematic review of non-RCTs with historical controls | |
| Non-RCT with historical controls | |
| Database, registry, or cross-sectional study | |
| Case series | |
| Retrospective review, modelling | |
| Studies presented at an international conference | |
| Expert opinion | |
| Total | 14 |
Abbreviation: RCT, randomized controlled trial.
The 14 systematic reviews assessed 14 factors affecting the likelihood of having a caesarean delivery in a low-risk obstetrical population: (21–34)
labour induction policy
epidural analgesia during labour
instrument choice for assisted vaginal delivery
electronic fetal monitoring
partogram to monitor progress of labour
package of care for active management during labour
oxytocin for induction of labour
gestational diabetes
glycemic control
maternal age
women's preference for caesarean delivery
maternal body mass index
assisted reproduction
group prenatal care
Labour Induction Policy
One Cochrane systematic review (26) assessed the effect on the caesarean delivery rate of a policy of labour induction at or beyond term compared with expectant management (defined in the study as awaiting spontaneous labour until a later gestational age or until a maternal or fetal indication for induction of labour was determined). The characteristics of this systematic review and its AMSTAR score (19) are reported in Table 2. Limitations in the AMSTAR rating are reported in Appendix 2.
Table 2:
Labour Induction Policy in Low-Risk Women at or Beyond Term Compared With Expectant Management
| Author, Year | Study Design Included | Search Dates | Intervention | Control | Other | AMSTAR Score |
|---|---|---|---|---|---|---|
| Gulmezoglu et al, 2012 (26) | RCT | Up to April 12, 2012 | Policy of labour induction at a predetermined gestational age | Expectant management until an indication for birth arises | Trial protocols differed according to gestational age, method of induction, and expectant management Population included low-risk women at or beyond term | 11/11 |
Abbreviations: AMSTAR, Assessment of Multiple Systematic Reviews; RCT, randomized controlled trial.
In the meta-analysis by Gulmezoglu et al, (26) 21 RCTs contributed to the comparison of a labour induction policy versus a policy of expectant management. The meta-analysis included 4,515 labouring women in the induction policy group and 4,234 in the expectant management group. Compared with a policy of expectant management, mothers who were managed with an induction policy had an 11% decrease in the caesarean delivery rate (relative risk [RR], 0.89; 95% confidence interval [CI], 0.81–0.97; I2 = 19%; fixed effect). This finding remained statistically significant in the gestational-age subgroup of 41 weeks, with a risk reduction of 26% (RR, 0.74; 95% CI, 0.58–0.96; fixed effect) in favour of induction policies. The lack of statistical significance in the other gestational-age subgroups (37–39 weeks, 39–40 weeks, < 41 weeks, and > 41 weeks) could have been due to inadequate optimal information size. Similarly, the lack of statistical difference among subgroups could have been due to the low number of studies in each subgroup, also leading to inadequate optimal information size. It was observed previously that when an induction policy postponed elective inductions to 39 weeks or after, patients spontaneously gave birth before the scheduled elective induction, resulting in lower rates of elective caesarean deliveries. (36)
Epidural Analgesia During Labour
One Cochrane systematic review (21) assessed the effect on the caesarean delivery rate of using epidural pain management compared with non-epidural analgesia or no analgesia in labour. The characteristics of this systematic review and its AMSTAR score (19) are reported in Table 3. Limitations in the AMSTAR rating are reported in Appendix 2.
Table 3:
Epidural Analgesia Compared With Non-Epidural Analgesia or No Analgesia
| Author, Year | Study Design Included | Search Dates | Intervention | Control | Other | AMSTAR Score |
|---|---|---|---|---|---|---|
| Anim-Somuah et al, 2011 (21) | RCT | Up to September 30, 2011 | All forms of epidural administration, including combined spinal epidural | No pain relief intervention or any form of pain relief not involving regional block | Pregnant women requesting pain relief, regardless of parity and whether labour was spontaneous or induced | 10/11 |
Abbreviations: AMSTAR, Assessment of Multiple Systematic Reviews; RCT, randomized controlled trial.
In the meta-analysis by Anim-Somuah et al, (21) 27 RCTs contributed to the comparison of epidural analgesia in labour compared with non-epidural analgesia or no analgesia. Among the 27 RCTs, 3 used combined spinal epidural, and the remainder used epidural analgesia. The meta-analysis included 4,223 labouring women in the epidural analgesia group and 4,194 in the non-epidural group. The caesarean delivery rate did not differ between groups (RR, 1.10; 95% CI, 0.97–1.25; I2 = 7%; fixed effect). However, compared to the non-epidural analgesia group, mothers who were managed with epidural analgesia during labour had a 43% increase in caesarean delivery rate due to fetal distress (RR, 1.43; 95% CI, 1.03–1.97; I2 = 0%; fixed effect; 11 studies; 4,816 women). Fetal distress was not defined in the systematic review. Of the 11 studies that contributed to this meta-analysis, 1 used combined spinal epidural analgesia, and the remainder used epidural analgesia; all participants were in spontaneous labour. A separate analysis from the same review found a 19% increase in oxytocin augmentation in the epidural group compared with the non-epidural analgesia group (RR, 1.19; 95% CI, 1.03–1.39; I2 = 90%; random effect; 13 studies; 5,815 women).
Instrument Choice for Assisted Vaginal Delivery
One Cochrane systematic review (30) assessed the effect on the caesarean delivery rate of using any type of forceps compared with any type of ventouse in assisted vaginal delivery. The characteristics of this systematic review and its AMSTAR score (19) are reported in Table 4. Limitations in the AMSTAR rating are reported in Appendix 2.
Table 4:
Any Type of Forceps Compared With Any Type of Ventouse for Assisted Vaginal Delivery
| Author, Year | Study Design Included | Search Dates | Intervention | Control | Other | AMSTAR Score |
|---|---|---|---|---|---|---|
| O'Mahony et al, 2010 (30) | RCT | Up to October 4, 2010 | Any type of forceps | Any type of ventouse | Women in the second stage of labour due for instrumental vaginal delivery; singleton cephalic pregnancies | 10/11 |
Abbreviations: AMSTAR, Assessment of Multiple Systematic Reviews; RCT, randomized controlled trial.
In the meta-analysis by O'Mahony et al (30), 4 RCTs contributed to the comparison of any type of forceps with any type of ventouse for assisted vaginal delivery. All RCTs included women with singleton cephalic pregnancies. Three RCTs included women at > 37 weeks' gestation, and 1 included women at 35 weeks' gestation. The meta-analysis included 615 labouring women in the forceps group and 607 in the ventouse group. The caesarean delivery rate did not differ between groups (RR, 1.76; 95% CI, 0.95–3.23; I2 = 0%; fixed effect). The systematic review also compared different types of forceps and ventouse instruments, but that comparison was outside the scope of this review. The systematic review did not complete a subgroup analysis of operator experience.
Electronic Fetal Monitoring
One Cochrane systematic review (25) assessed the effect on the caesarean delivery rate of cardiotocography (CTG) compared with intermittent auscultation of the fetal heart on admission to the labour ward. The characteristics of this systematic review and its AMSTAR score (19) are reported in Table 5. Limitations in the AMSTAR rating are reported in Appendix 2.
Table 5:
CTG Compared With Intermittent Auscultation on Admission to the Labour Ward in Low-Risk Women
| Author, Year | Study Design Included | Search Dates | Intervention | Control | Other | AMSTAR Score |
|---|---|---|---|---|---|---|
| Devane et al, 2012 (25) | RCT | Up to November 2011 | CTG at admission to labour ward | Intermittent auscultation of the fetal heart rate on admission to labour ward | Women at 37 to 42 completed weeks of pregnancy and at low risk for intrapartum fetal hypoxia and developing complications during labour | 10/11 |
Abbreviations: AMSTAR, Assessment of Multiple Systematic Reviews; CTG, cardiotocography; RCT, randomized controlled trial.
In the meta-analysis by Devane et al, (25) 4 RCTs contributed to the comparison of CTG with intermittent auscultation in low-risk women. The meta-analysis included 5,657 labouring women in the CTG group and 5,681 in the intermittent auscultation group. Compared with intermittent auscultation, there was a 20% increase in the caesarean delivery rate when CTG was used on admission to the labour ward in low-risk women (RR, 1.20; 95% CI, 1.00–1.44; I2 = 0%; random effect). Given that the lower CI interval was 1.00 and the absence of statistical heterogeneity in the analysis, the authors concluded that CTG was likely to increase the caesarean delivery rate by approximately 20%. If the data from this meta-analysis were reversed to report a good outcome, there would be a 17% decrease in the caesarean delivery rate in favour of intermittent auscultation at admission (RR, 0.83; 95% CI, 0.69–1.00; I2 = 0%; random effects model). The authors also reported that compared with intermittent auscultation, CTG on admission was associated with a statistically significant 30% increase in continuous electronic fetal monitoring during labour in low-risk women (RR, 1.30; 95% CI, 1.14–1.48; 3 studies; 10,753 women).
Partogram to Monitor Progress of Labour
One Cochrane systematic review (27) assessed the effect on the caesarean delivery rate of partogram during labour compared with no partogram. The characteristics of this systematic review and its AMSTAR score (19) are reported in Table 6. Limitations in the AMSTAR rating are reported in Appendix 2.
Table 6:
Partogram Compared With No Partogram During Labour in Women With Spontaneous Term Pregnancies
| Author, Year | Study Design Included | Search Dates | Intervention | Control | Other | AMSTAR Score |
|---|---|---|---|---|---|---|
| Lavender et al, 2012 (27) | RCT | Up to June 2012 | Partogram use during labour | No partogram | Population included women with spontaneous term pregnancy | 10/11 |
Abbreviations: AMSTAR, Assessment of Multiple Systematic Reviews; RCT, randomized controlled trial.
In the meta-analysis by Lavender et al, (27) 2 RCTs contributed to the comparison of partogram during labour compared with no partogram in women with spontaneous term pregnancies. The meta-analysis included 804 labouring women in the partogram group and 786 in the no-partogram group. The caesarean delivery rate did not differ between groups (RR, 0.64; 95% CI, 0.24–1.70), but the I2 value was 93%, indicating high heterogeneity. Subgroup analysis for high and low resource settings indicated that compared to no partogram, using a partogram during labour in low-resource settings reduced the caesarean delivery rate by 62% (RR, 0.38; 95% CI, 0.24–0.61; 1 trial; random effect; 434 women); the rate did not differ between groups in high-resource settings (RR, 1.03; 95% CI, 0.82–1.28; random effect; 1 trial; 1,156 women).
Package of Care for Active Management During Labour
One Cochrane systematic review (23) assessed the effect on the caesarean delivery rate of following a predefined package of interventions during labour compared to routine care in low-risk women. The characteristics of this systematic review and its AMSTAR score (19) are reported in Table 7. Limitations in the AMSTAR rating are reported in Appendix 2.
Table 7:
Package of Care for Active Management in Labour Compared With Routine Care in Low-Risk Women
| Author, Year | Study Design Included | Search Dates | Intervention | Control | Other | AMSTAR Score |
|---|---|---|---|---|---|---|
| Brown et al, 2008 (23) | RCT | Up to February 28, 2008 | A predefined interventionist package of active management during childbirth | Routine care as per care setting, local labour-ward management protocols, and the variable practice of clinicians | Predefined package of care had to include more than 2 of the key elements traditionally described as active management of labour including routine amniotomy and early augmentation with oxytocin; strict criteria for the diagnosis of labour, abnormal progress in labour, and fetal compromise; continual presence of a midwife/nurse during labour; peer review of assisted deliveries; and progress of labour plotted using a graph) Low-risk population | 10/11 |
Abbreviations: AMSTAR, Assessment of Multiple Systematic Reviews; RCT, randomized controlled trial.
In the meta-analysis by Brown et al, (23) 7 RCTs contributed to the comparison of a package of care for active management in labour compared with routine care (no package of care) in low-risk women. The meta-analysis included 2,573 labouring women in the package of care group and 2,817 in the routine care group. The caesarean delivery rate did not differ between groups (RR, 0.88; 95% CI, 0.77–1.01; I2 = 21%; fixed effect). The authors of the meta-analysis noted that 1 RCT (37) had a 35% drop-out rate in both treatment groups combined post-randomization but before the onset of labour. This study (37) was given the most weight in the meta-analysis. When a sensitivity analysis was completed removing this study, the results indicated a statistically significant decrease in caesarean delivery rate in the package of care group compared with the routine care group (RR, 0.77; 95% CI, 0.63–0.94; I2 = 0%; fixed effect; 6 trials; 3,475 women). Nevertheless, the authors (37) noted that while a large number of post-randomization exclusions occurred in the trial, outcome data were provided for these exclusions, and there was a < 1% attrition rate for this outcome. Because of this, the nonsignificant findings of the meta-analysis, including all the 7 studies, were accepted for this review.
Oxytocin for Induction of Labour
One Cochrane systematic review (24) assessed the effect on the caesarean delivery rate of oxytocin for the treatment of slow progress in the first stage of spontaneous labour. The characteristics of this systematic review and its AMSTAR score (19) are reported in Table 8. Limitations in the AMSTAR rating are reported in Appendix 2.
Table 8:
Oxytocin to Augment Labour in Low-Risk Women
| Author, Year | Study Design Included | Search Dates | Intervention | Control | Other | AMSTAR Score |
|---|---|---|---|---|---|---|
| Bugg et al, 2011 (24) | RCT | Up to June 5, 2011 | Intravenous oxytocin to augment labour (women who commenced oxytocin for poor progress in the active stage of labour) | Placebo or no treatment with oxytocin or in whom the treatment with oxytocin was delayed | Low-risk pregnant women who were slow to progress in the first stage of spontaneous labour at 37–42 weeks and a singleton fetus presenting vertex Women with a previous caesarean delivery or who were induced with oxytocin from the outset were excluded | 10/11 |
Abbreviations: AMSTAR, Assessment of Multiple Systematic Reviews; RCT, randomized controlled trial.
In the meta-analysis by Bugg et al, (24) 3 RCTs contributed to the comparison of intravenous oxytocin compared with no treatment in low-risk women. The meta-analysis included 65 labouring women in the intravenous oxytocin group and 73 in the no-treatment group. The caesarean delivery rate did not differ between groups (RR, 0.84; 95% CI, 0.36–1.96; I2 = 0%; fixed effect).
Gestational Diabetes
One systematic review (34) assessed the effect on the caesarean delivery rate of gestational diabetes mellitus (GDM) diagnosed by either the WHO or the International Association of the Diabetes in Pregnancy Study Group (IADPSG) criteria. The characteristics of this systematic review and its AMSTAR score (19) are reported in Table 9. Limitations in the AMSTAR rating are reported in Appendix 2.
Table 9:
Gestational Diabetes Mellitus and Caesarean Delivery
| Author, Year | Study Design Included | Search Dates | Cohort 1 | Cohort 2 | Other | AMSTAR Score |
|---|---|---|---|---|---|---|
| Wendland et al, 2012 (34) | Cohort studies (retrospective and prospective) | Up to March 15,2011 | GDM diagnosed by WHO and/or IADPSG criteria | Women without GDM | — | 9/11 |
Abbreviations: AMSTAR, Assessment of Multiple Systematic Reviews; GDM, gestational diabetes mellitus, IADPSG, International Association of the Diabetes in Pregnancy Study Group; NA, not applicable; WHO, World Health Organization.
In the meta-analysis by Wendland et al, (34) 5 cohort studies (4 prospective and 1 retrospective) contributed to the evaluation of GDM and caesarean delivery. Compared to women without GDM, women diagnosed with GDM using the WHO criteria had a 37% higher risk of having a caesarean delivery (RR, 1.37; 95% CI, 1.24–1.51; random effects model; 4 trials; 30,045 women). The I2 value was 29%, indicating low heterogeneity across the 4 trials using the WHO criteria. Women diagnosed with GDM using the IADSG criteria had a 23% higher risk of having a caesarean delivery compared to a non-GDM cohort (RR, 1.23; 95% CI, 1.01–1.51; random effects model; 3 trials; 33,788 women). The I2 value was 93%, indicating high heterogeneity across the 3 studies using the IADPSG criteria. In both analyses, women with GDM had a statistically significant higher risk of having a caesarean delivery compared to women without GDM.
Glycemic Control
One Cochrane systematic review (29) assessed the effect on the caesarean delivery rate of different intensities of glycemic control (tight versus very tight) in low-risk pregnant women with pre-existing type 1 or 2 diabetes. The characteristics of this systematic review and its AMSTAR score (19) are reported in Table 10. Limitations in the AMSTAR rating are reported in Appendix 2.
Table 10:
Tight-Moderate Glycemic Control Compared With Loose Glycemic Control in Low-Risk Women With Pre-existing Type 1 or 2 Diabetes
| Author, Year | Study Design Included | Search Dates | Intervention | Control | Other | AMSTAR Score |
|---|---|---|---|---|---|---|
| Middleton et al, 2012 (29) | RCT, nRCT | Up to May 24, 2012 | Tight-moderate glycemic control (fasting blood glucose <6.7 mmol/L) | Loose glycemic control (fasting blood glucose 6.7–8.9 mmol/L) | Population included pregnant women with pre-existing type 1 or 2 diabetes | 10/11 |
Abbreviations: AMSTAR, Assessment of Multiple Systematic Reviews; nRCT, nonrandomized controlled trial; RCT, randomized controlled trial.
In the meta-analysis by Middleton et al, (29) 1 RCT contributed to the comparison of tight-moderate glycemic control with loose glycemic control in women with pre-existing type 1 or 2 diabetes. This study was completed in Saudi Arabia. (38) Tight glycemic control in this study was defined as a target of 5.6 mmol/L or below (n = 16 women), moderate glycemic control was defined as a target of 5.6 to 6.7 mmol/L (n = 29 women) and loose glycemic control was defined as a target of 6.7 to 8.9 mmol/L (n = 15 women). (38) The study did not specify whether blood glucose was fasting, but the authors assumed that it was. (29) For the purposes of meta-analysis, the tight and moderate glycemic control groups were combined and compared to the loose glycemic control group (45 labouring women in the tight-moderate glycemic control group and 15 in the loose glycemic control group). Compared to women with loose glycemic control, women with tight-moderate glycemic control had a 72% decrease in caesarean delivery rate (RR, 0.28; 95% CI, 0.10–0.78; fixed effect). (29)
Maternal Age
One systematic (22) review assessed the effect on the caesarean delivery rate of advanced maternal age among nulliparous and multiparous women. The characteristics of this systematic review and its AMSTAR score (19) are reported in Table 11. Limitations in the AMSTAR rating are reported in Appendix 2.
Table 11:
Maternal Age and Caesarean Delivery
| Author, Year | Study Design Included | Search Dates | Cohort 1 | Cohort 2 | Other | AMSTAR Score |
|---|---|---|---|---|---|---|
| Bayrampour and Heaman, 2010 (22) | Cohort, case control | January 1, 1995, to March 1, 2008 | 35 years or older | 34 years or younger | Nulliparous and multiparous women with singleton pregnancies Compared total caesarean deliveries, including emergency or elective Studies done in developed countries only | 6/11 |
Abbreviations: AMSTAR, Assessment of Multiple Systematic Reviews.
In the meta-analysis by Bayrampour and Heaman, (22) 21 RCTs contributed to the comparison of maternal age 35 years or older with maternal age 34 years and younger. The relative risk for caesarean delivery in nulliparous women 35 years of age and older compared with those 34 years of age and younger was 1.44 to 2.27 (I 2 = 91%), estimated from 12 studies (random effects model) and a total sample size of 561,352 women. In 25,598 older multiparas women, the relative risk for caesarean delivery was 1.63 to 2.78 (I2 = 94%). Due to high heterogeneity in both estimates, a pooled effect estimate was not reported. Most studies in the analysis reported the total caesarean delivery rate, which included both emergency and elective deliveries. Fifteen of the 21 studies adjusted for potential confounders, including sociodemographic factors (race/ethnicity, education, parity, and marital status), smoking, maternal height, assisted conception, duration of labour, induced labour, fetal distress, epidural anesthesia, and physician and hospital factors. Each study controlled for different confounder variables; prepregnancy body mass, gestational age, birth weight, history of chronic disease, and pregnancy complications were the most frequently controlled.
Women's Preference for Caesarean Delivery
One systematic review (28) assessed the effect of women's preference for a caesarean delivery compared with vaginal delivery. This study also reported the proportion of women who preferred a caesarean delivery by subgroup according to study characteristics and women's characteristics. A random-effect metaregression analysis was used to determine which variables were significantly associated with a caesarean delivery preference. The characteristics of this systematic review and its AMSTAR score (19) are reported in Table 12. Limitations in the AMSTAR rating are reported in Appendix 2.
Table 12:
Women's Preference for a Caesarean Delivery Compared With a Vaginal Delivery
| Author, Year | Study Design Included | Search Dates | Cohort | AMSTAR Score |
|---|---|---|---|---|
| Mazzoni et al, 2011 (28) | Cross-sectional, cohort | Up to March 2009 | Study determined the preference for caesarean delivery in subgroups according to study characteristics (study region, country income level, and year of study) and women's characteristics (history of previous caesarean delivery, parity, and period of reproductive life when preference was evaluated) | 8/11 |
Abbreviations: AMSTAR, Assessment of Multiple Systematic Reviews.
In the meta-analysis by Mazzoni et al, (28) 32 cross-sectional and 6 cohort studies contributed to the analysis of women's preference for a caesarean delivery. Of 19,403 women, 15.6% (95% CI, 12.5%–18.9%) preferred a caesarean delivery; the I2 was 97.3% for this overall estimate. Of 616 nulliparous women, 10.2% (95% CI, 6.8%–14.1%) preferred a caesarean delivery. Of 12,677 multiparous women, 17.5% (95% CI, 13.4%–21.8%) preferred a caesarean delivery. Of women who had had a previous caesarean delivery (n = 4,010) 29.4% preferred a caesarean delivery (95% CI, 24.4%–34.8%), compared with 10.1% (95% CI, 7.5%–13.1%) of women who had not had a previous caesarean delivery (n = 13,922). The rate for the United States and Canada combined, regardless of parity or previous caesarean delivery experience, was 16.8% (95% CI, 7.9%–28.1%; 6 nonrandomized controlled trials; I2 ranged from 82.2% to 98.5%). In the multivariate metaregression analysis, after adjusting for other characteristics, women with a previous caesarean delivery and women from middle-income countries were significantly more likely to prefer a caesarean delivery compared to women without a history of caesarean delivery and women from high-income countries.
Maternal Body Mass Index
One systematic review (32) assessed the effect on the caesarean delivery rate of maternal body mass index (BMI). The characteristics of this systematic review and its AMSTAR (19) rating are reported in Table 13. Limitations in the AMSTAR rating are reported in Appendix 2.
Table 13:
Maternal BMI as a Risk Factor for Caesarean Delivery in Low-Risk Women
| Author, Year | Study Design Included | Search Dates | Cohort 1 | Cohort 2 | Other | AMSTAR Score |
|---|---|---|---|---|---|---|
| Poobalan et al, 2009 (32) | Retrospective and prospective cohort | 1966 to 2007 | Overweight (BMI 25–30 kg/m2) Obese (BMI 30–35 kg/m2) Morbidly obese (BMI > 35 kg/m2) | Normal weight (BMI 20–25 kg/m2) | Nulliparous singleton pregnancy All elective caesarean deliveries | 7/11 |
Abbreviations: AMSTAR, Assessment of Multiple Systematic Reviews; BMI, body mass index.
In the meta-analysis by Poobalan et al, (32) 11 cohort studies (7 retrospective, 4 prospective) contributed to the analysis of the association between maternal BMI ≥ 25 kg/m2 and caesarean delivery. Five studies were completed in the United States, 3 in the United Kingdom, 1 in Denmark, 1 in Sweden, and 1 in France. Compared to mothers with a normal BMI, overweight women were at 1.5 times higher risk of caesarean delivery (odds ratio, 1.5; 95% CI, 1.48–1.58; 10 studies; random effect; 43,025 women), obese women were at 2.3 times higher risk (odds ratio, 2.26; 95% CI, 2.04–2.51; random effect; 11 studies; 20,419 women) and morbidly obese women were at 3.4 times higher risk (odds ratio, 3.38; 95% CI, 2.49–4.57; random effect; 4 studies; 1,874 women).
Assisted Reproduction
One systematic review (31) assessed the effect on the caesarean delivery rate of in vitro fertilization (IVF)/intracytoplasmic sperm injection (ICSI) assisted pregnancy. The characteristics of this systematic review and its AMSTAR score (19) are reported in Table 14. Limitations in the AMSTAR rating are reported in Appendix 2.
Table 14:
Women Who Had an IVF/ICSI-Assisted Pregnancy Compared With Women Who Had Spontaneous Conception Pregnancies
| Author, Year | Study Design Included | Search Dates | Cohort 1 | Cohort 2 | Other | AMSTAR Score |
|---|---|---|---|---|---|---|
| Pandey et al, 2012 (31) | Matched and unmatched cohort studies | 1978–2011 | IVF/ICSI assisted conception | Spontaneous conception | Singleton pregnancies Many women delivered at less than 37 weeks | 9/11 |
Abbreviations: AMSTAR, Assessment of Multiple Systematic Reviews; IVF, in vitro fertilization; ICSI, intracytoplasmic sperm injection.
In the meta-analysis by Pandey et al, (31) 17 cohort studies (14 matched and 3 unmatched) contributed to the comparison of assisted reproduction (IVF/ICSI) pregnancies with spontaneous pregnancies. The meta-analysis included 18,186 IVF/ICSI conceptions and 584,938 spontaneous conceptions. Compared with pregnancies via spontaneous conception, women who conceived using IVF/ICSI were 56% more likely to have a caesarean delivery (RR, 1.56; 95% CI 1.51–1.60; I2 = 80%; fixed effect; 17 trials; 603,124 women). On subgroup analysis, this finding remained statistically significant, with a 47% increase in matched cohort studies (RR, 1.47; 95% CI, 1.38–1.56; fixed effect; 14 trials; 13,959 women) and a 59% increase in unmatched cohort studies (RR, 1.59; 95% CI, 1.54–1.64; fixed effect; 3 trials; 96,606 women). However, the I2 values for the matched and unmatched cohort subgroup analyses were 78% and 86%, respectively. Sixteen of the 17 studies included preterm deliveries (< 37 weeks). It was not possible to isolate the caesarean delivery rate in the IVF/ICSI population with term pregnancies.
Group Prenatal Care
One systematic review (33) assessed the effect on the caesarean delivery rate of group prenatal care in low-risk women compared with individual prenatal care. The characteristics of this systematic review and its AMSTAR score (19) are reported in Table 15. Limitations in the AMSTAR rating are reported in Appendix 2.
Table 15:
Group Prenatal Care Compared With Individual Prenatal Care in Low-Risk Women
| Author, Year | Study Design Included | Search Dates | Intervention | Control | Other | AMSTAR Score |
|---|---|---|---|---|---|---|
| Ruiz-Mirazo et al, 2012 (33) | RCT, nRCT | Up to June 5, 2011 | Group prenatal care | Individual prenatal care | Low-risk pregnant women Nulliparous and multiparous | 7/11 |
Abbreviations: AMSTAR, Assessment of Multiple Systematic Reviews; nRCT, nonrandomized controlled trial; RCT, randomized controlled trial.
In the systematic review by Ruiz-Mirazo et al, (33) 1 RCT reported on the outcome of caesarean delivery. The RCT by Jafari et al (39) was a cluster RCT; 320 women received group prenatal care and 308 received individual prenatal care. The study was completed in Iran. Compared with individual prenatal care, women who received group prenatal care had a 20% reduction in caesarean delivery (RR, 0.80; 95% CI 0.65–0.99; fixed effect; 1 trial; 628 women).
Summary
A summary of the factors affecting the likelihood of caesarean delivery is reported in Table 16. Elective induction policies and group prenatal care decreased the likelihood of caesarean delivery in low-risk women.
Table 16:
Summary of Factors Affecting the Likelihood of Caesarean Delivery in Low-Risk Women
| Increases Likelihood | Decreases Likelihood | No Influencea |
|---|---|---|
| Electronic fetal monitoring (cardiotocography) | Labour induction policyf | Epidural analgesia during labour |
| Group prenatal careg | Oxytocin for induction of labour | |
| Loose glycemic controlb Gestational diabetes | Instrument choice for assisted vaginal delivery | |
| Assisted reproductionc | Partogram to monitor progress of labourh | |
| Maternal body mass indexd Women's preference for caesarean delivery | Package of care for active management during labour | |
| Maternal agee |
No statistical difference between treatment (factor) and comparator.
In mothers with type 1 and 2 diabetes.
In vitro fertilization/intracytoplasmic sperm injection.
Women with body mass index ≥ 25 kg/m2.
In women ≥ 35 years of age.
In women at 41 weeks' gestation or beyond.
One randomized controlled trial.
In high resource settings.
A forest plot for the outcome of caesarean delivery for group prenatal care is provided in Appendix 3. The GRADE quality of evidence is reported in Appendix 2: the quality of evidence for an elective induction policy at 41 weeks compared with expectant management was high, and the quality of evidence for group prenatal care compared with individual care was low.
Provincial Rate Review
Research Methods
We used clinical and administrative data on caesarean deliveries in Ontario to evaluate potential rate variation across the province and whether such variation could be attributed to practice differences or maternal factors. At each stage of analysis, the expert panel provided input on the findings and guidance on subsequent analyses.
Provincial Caesarean Delivery Rates
The Canadian Institute for Health Information Discharge Abstracts Database provides data on all hospitalizations in Ontario, including information on deliveries that occur in hospitals. Clinical records for mothers and infants have been linked at the Institute for Clinical Evaluative Sciences (ICES) to create a unified hospital record in the Mother-Baby Linked Database (MOMBABY) (40) of delivering mothers and their newborns. The dataset includes information on maternal gestational age at admission and at delivery, newborn gestational age (in weeks) at delivery and flags that identify multiple births and stillbirths. These data were used to conduct a preliminary review of caesarean delivery rates in Ontario in calendar years 2007–2011 for all women in Ontario; women with full-term, singleton, vertex presentations and no evidence of previous caesarean delivery; women with a breech presentation; and women with a history of caesarean delivery.
Data were stratified by age group (< 21 years, 21–34 years, 35+ years), and rates were prepared by LHIN, rural versus urban location of the mother, and hospital maternal level of care as defined by the Provincial Centre for Maternal and Child Health (PCMCH). Level of care is intended to categorize hospitals according to the intensity of maternal and infant care and is based on staffing levels, staff availability, and onsite intensive care provision. Levels are ordered from low to high: 1, 2, 2+, 3 modified, and 3. Level 3 hospitals can provide care for deliveries with the most risk and infants with the most complex illnesses. (41)
Provincial Caesarean Delivery Rates Among Low-Risk Women
The preliminary analyses were presented to the expert panel, and based on their feedback, the cohort was limited to low-risk women and the data source changed from the ICES MOMBABY dataset (40) to the clinical database from the Better Outcomes and Registry Network (BORN) Ontario. (42) BORN integrates data on prenatal care, delivery, and postpartum care in a mother-child registry. Data are collected from a number of sources and include information on maternal characteristics, labour, birth, and early newborn care. Deliveries can be classified by Robson group (see below), and delivering hospitals can be classified by delivery volume (for any given year), PCMCH level of care, and hospital peer group (small community, large community, academic).
For the BORN analyses, the cohort was limited, based on information from hospital records,1 to women who were classified as part of Robson groups 1, 2a, and 2b. (43) Robson groups represent a standard classification system of 10 mutually exclusive and totally inclusive classification categories for deliveries:
-
1.
Nulliparous, singleton, cephalic, term, spontaneous labour
-
2a.
Nulliparous, singleton, cephalic, term, induced labour
-
2b.
Nulliparous, singleton, cephalic, term, caesarean delivery before labour
Caesarean delivery rates for 5 fiscal years were prepared by Robson group and reported by fiscal year (2007/2008 to 2011/2012) at the provincial and LHIN levels. Rates were also compared across a set of maternal characteristics (maternal age, neighbourhood income quintile, neighbourhood educational attainment, rural/urban status, and primary language).
Provincial Caesarean Delivery Rates Among a Very-Low-Risk Subgroup of Women
Based on the findings of the second set of analyses, the expert panel recommended a follow-up analysis. Caesarean delivery rates in a further refined subgroup of women were compared at the provincial, LHIN, and hospital levels. Five years of cumulative data (fiscal years 2007/2008 to 2011/2012) on caesarean delivery rates among women who delivered in hospital were prepared for a more homogeneous group of women:
Robson 1, 2a, and 2b
aged 20 to 34 years
no maternal medical problems
no obstetrical complications
Women with the following indications for caesarean delivery were excluded: cord prolapse, diabetes, fetal anomaly, placental abruption, placenta previa, pre-eclampsia, other fetal health problem, other maternal health problem.
The objective of creating a very low-risk cohort was to eliminate a number of indications for caesarean delivery, thereby reducing or limiting potential clinical reasons for variation in rates. The following 5 indications for caesarean delivery were not incorporated as cohort exclusions: failure of descent/progress (dystocia); intrauterine growth restriction or small for gestational age; large for gestational age; non-reassuring fetal status; and premature rupture of membranes.
Rates were prepared by LHIN; hospital PCMCH level of care (1, 2, 2+, modified 3, 3); hospital birth volume in 2011/2012 (≤ 100, 101–250, 251–500, 501–1,000, 1,001–2,499, 2,500–4,000, >4,000); and by hospital, with rates grouped by PCMCH level of care and birth volume.
Results of Provincial Rate Review
Provincial Caesarean Delivery Rates
Caesarean delivery rates in Ontario for all women who deliver in hospital were stable over time for the overall population and within age strata. Rates were lowest in women under age 20; women aged 35 and older had approximately twice the caesarean delivery rate as the youngest age group. The overall provincial caesarean delivery rate for 2007 to 2011 hovered around 28% (Table 17). The expert panel felt there was little evidence of clinically important variation in caesarean delivery rates by LHIN or over time.
Table 17:
Caesarean Delivery Rates Among Ontario Women Who Delivered in Hospital, by Age and Calendar Year
| Age Group | 2007 | 2008 | 2009 | 2010 | 2011 | |||||
|---|---|---|---|---|---|---|---|---|---|---|
| % | N | % | N | % | N | % | N | % | N | |
| ≤ 20 | 18.1 | 7,769 | 18.3 | 7,766 | 17.6 | 7,510 | 17.3 | 7,167 | 18.4 | 6,631 |
| 21–34 | 26.3 | 99,092 | 26.8 | 99,080 | 26.6 | 98,489 | 26.7 | 96,550 | 26.6 | 96,807 |
| 35+ | 35.9 | 28,039 | 37.7 | 28,473 | 37.3 | 28,590 | 37.6 | 29,066 | 37.6 | 29,152 |
| Total | 27.8 | 134,900 | 28.6 | 135,319 | 28.4 | 134,589 | 28.6 | 132,783 | 28.6 | 132,590 |
Abbreviations: ICES, Institute for Clinical Evaluative Sciences; MOMBABY, Mother-Baby Linked Database.
Source: ICES-MOMBABY dataset. (40)
Provincial Caesarean Delivery Rates Among Low-Risk Women
Based on expert panel consensus, the cohort was restricted to a low-risk group consisting of women classified as Robson group 1, 2a, and 2b when presenting to hospital. Provincial rates were reported for 5 fiscal years to assess the stability of the rates over time. Similar to what was seen in the preliminary analysis, rates and relative proportions across Robson groups were consistent over time (Table 18). As expected, rates for women in Robson group 2b were close to 100%, but this group of women accounted for only about 3% of total deliveries. Women in Robson group 2a had twice the rate of caesarean deliveries that women in Robson group 1 did. However, this finding should be interpreted with caution, because Robson class is established at hospital presentation. Women who undergo induction in an office setting may be classified as being in spontaneous labour (Robson 1) when the present to hospital, but should actually be classified as having been induced (Robson 2a).
Table 18:
Caesarean Delivery Rates Among Ontario Women Who Delivered in Hospital, by Robson Group (1, 2a, 2b, and Combined) and Fiscal Year
| Robson Group | 2007/2008 | 2008/2009 | 2009/2010 | 2010/2011 | 2011/2012 | |||||
|---|---|---|---|---|---|---|---|---|---|---|
| % | N | % | N | % | N | % | N | % | N | |
| 1 | 15.1 | 31,180 | 15.5 | 32,116 | 14.6 | 32,212 | 14.6 | 31,285 | 15.4 | 31,918 |
| 2a | 30.3 | 15,153 | 31.1 | 15,970 | 30.6 | 16,429 | 30.4 | 15,419 | 30.7 | 15,348 |
| 2b | 100.0 | 1,519 | 99.9 | 1,650 | 100.0 | 1,549 | 100.0 | 1,567 | 100.0 | 1,628 |
| Combined | 22.6 | 47,852 | 23.3 | 49,736 | 22.5 | 50,190 | 22.4 | 48,271 | 23.0 | 48,894 |
Abbreviations: BORN, Better Outcomes and Registry Network.
Source: BORN Ontario. (42)
BORN data were also used to evaluate variations in caesarean delivery rates across a number of maternal demographic factors, including maternal age, neighbourhood income quintile, neighbourhood educational attainment, rural/urban status, and primary language. As expected, higher maternal age was significantly associated with an increase in caesarean delivery rates (P < 0.001), but the remaining demographic factors showed no consistent significant association with caesarean delivery rates (Table 19).
Table 19:
Caesarean Delivery Rates for Robson Groups 1 and 2a by Maternal Characteristics (2011/2012)
| Characteristic | Groups | Robson 1 | Robson 2a | ||
|---|---|---|---|---|---|
| % | N | % | N | ||
| Maternal age | <21 years | 9.7 | 3,136 | 20.2 | 1,314 |
| 21–34 years | 14.9 | 25,062 | 29.7 | 11,805 | |
| 35–39 years | 22.6 | 3,098 | 40.5 | 1,779 | |
| 40+ years | 28.4 | 592 | 48.2 | 446 | |
| P value | <0.001 | — | <0.001 | — | |
| Neighbourhood income quintile | 1 | 15.6 | 6,182 | 31.7 | 2,981 |
| 2 | 15.4 | 6,176 | 31.2 | 2,980 | |
| 3 | 15.5 | 6,178 | 30.1 | 2,979 | |
| 4 | 14.9 | 6,194 | 30.7 | 2,989 | |
| 5 | 15.5 | 6,163 | 29.8 | 2,971 | |
| P value | 0.83 | — | 0.48 | — | |
| Neighbourhood educational attainment | Less than high school | 15.5 | 5,640 | 30.3 | 2,840 |
| High schoola | 15.3 | 15,014 | 31.0 | 7,253 | |
| Postsecondary | 15.3 | 10,505 | 30.4 | 4,945 | |
| P value | 0.55 | — | 0.73 | — | |
| Rural/urban status | Rural | 15.0 | 3,507 | 27.5 | 1,831 |
| Urban | 15.4 | 28,276 | 31.1 | 13,473 | |
| P value | 0.53 | — | 0.001 | — | |
| Primary language | English | 15.6 | 26,031 | 30.7 | 12,892 |
| French | 17.6 | 477 | 30.7 | 192 | |
| Other | 14.0 | 2,785 | 29.3 | 1,057 | |
| P value | 0.04 | — | 0.64 | — | |
Abbreviations: BORN, Better Outcomes and Registry Network.
Did not complete postsecondary.
Source: BORN Ontario, mothers who delivered in hospital. (42)
The analysis also included an evaluation of regional variation in caesarean delivery rates for women in Robson groups 1 and 2a to assess whether there was any clinically important variation in rates across LHINs. Table 20 presents the rates for women in Robson groups 1 and 2a for 5 fiscal years by LHIN. The rates for women in Robson group 2b were close to 100% in all LHINs and over time, and so are not included in the table.
Table 20:
Caesarean Delivery Rates for Robson Groups 1 and 2a by LHIN (2007/2008–2011/2012)
| LHIN | 2007/2008 | 2008/2009 | 2009/2010 | 2010/2011 | 2011/2012 | |||||
|---|---|---|---|---|---|---|---|---|---|---|
| 1 | 2a | 1 | 2a | 1 | 2a | 1 | 2a | 1 | 2a | |
| 1 | 12.2 | 27.2 | 11.9 | 27.0 | 13.1 | 29.0 | 12.3 | 29.6 | 14.5 | 28.3 |
| 2 | 11.7 | 24.7 | 12.0 | 25.9 | 10.1 | 24.0 | 10.4 | 24.0 | 10.3 | 25.2 |
| 3 | 14.1 | 29.8 | 12.8 | 30.7 | 12.9 | 27.1 | 14.9 | 29.9 | 14.1 | 29.6 |
| 4 | 17.8 | 32.8 | 16.2 | 33.7 | 15.0 | 30.7 | 12.4 | 28.8 | 14.1 | 26.8 |
| 5 | 14.3 | 32.5 | 18.7 | 39.9 | 18.8 | 36.5 | 18.6 | 37.6 | 20.7 | 37.9 |
| 6 | 12.9 | 28.3 | 13.4 | 26.2 | 12.5 | 28.5 | 12.5 | 30.4 | 11.9 | 29.8 |
| 7 | 16.5 | 32.4 | 15.3 | 32.3 | 16.4 | 32.5 | 15.8 | 31.0 | 16.3 | 32.8 |
| 8 | 16.6 | 31.0 | 17.1 | 31.3 | 15.1 | 28.7 | 14.3 | 30.4 | 16.3 | 29.9 |
| 9 | 15.1 | 34.1 | 17.8 | 33.0 | 15.7 | 37.2 | 16.1 | 32.2 | 16.9 | 33.1 |
| 10 | 13.9 | 29.5 | 14.8 | 32.4 | 16.4 | 310 | 16.3 | 30.3 | 16.4 | 33.3 |
| 11 | 15.0 | 25.7 | 16.3 | 33.4 | 12.8 | 28.5 | 15.1 | 31.2 | 160 | 29.3 |
| 12 | 18.4 | 32.2 | 16.5 | 30.9 | 17.1 | 36.6 | 16.2 | 30.0 | 18.8 | 35.3 |
| 13 | 12.8 | 31.5 | 14.7 | 30.5 | 14.0 | 32.2 | 14.5 | 30.5 | 14.5 | 32.6 |
| 14 | 18.7 | 33.7 | 12.2 | 27.8 | 14.3 | 33.9 | 16.7 | 34.4 | 14.5 | 34.5 |
| Ontario | 15.1 | 30.3 | 15.5 | 31.1 | 14.6 | 30.6 | 14.6 | 30.4 | 15.4 | 30.7 |
Abbreviation: BORN, Better Outcomes and Registry Network; LHIN, Local Health Integration Network.
Source: BORN Ontario, mothers who delivered in hospital. (42)
Rates across LHINs varied by approximately 10% (from lowest to highest rates) for women in both Robson groups, but the expert panel did not feel that this variation was clinically important, or that it represented practice variation. The large geographic units and potentially unaccounted differences (by region) in clinically important maternal factors were believed to explain the observed variation, as well as hospital-level differences related to catchment, delivery volumes, and practice patterns. For this reason, the expert panel felt that data at the hospital level were needed to answer the research question.
Provincial Caesarean Delivery Rates Among a Very-Low-Risk Subgroup of Women
The final set of analyses was constructed for a more homogeneous, lower-risk group of women and reported at the LHIN and hospital levels. The rationale was that observed variation in this cohort at the regional or hospital level could more easily be interpreted. Data for 5 fiscal years were combined to ensure sufficient cell size.
LHIN
LHIN variation in caesarean delivery rates in this very-low-risk cohort of women mirrored what was observed in previous analyses (Table 21). While the difference between the highest and lowest LHIN rates was striking, the difference across the remaining LHINs did not raise concerns among the expert panel.
Table 21:
Caesarean Delivery Rates for Robson Groups 1 and 2a in a Very-Low-Risk Cohorta by LHIN (2007/2008–2011/2012)
| LHIN | Robson 1 | Robson 2a | Combined (1, 2a, 2b) | |||
|---|---|---|---|---|---|---|
| % (95% CI) | N | % (95% CI) | N | % (95% CI) | N | |
| 1 | 10.9 (9.7–12.1) | 2,740 | 27.1 (24.7–29.6) | 1,335 | 16.8 (15.6–17.9) | 4,103 |
| 2 | 6.6 (5.8–7.5) | 3,267 | 16.5 (14.4–18.8) | 1,114 | 9.7 (8.8–10.6) | 4,409 |
| 3 | 12.4 (11.4–13.3) | 4,705 | 26.8 (24.8–28.9) | 1,772 | 17.0 (16.1–17.9) | 6,528 |
| 4 | 12.4 (11.7–13.2) | 7,610 | 26.6 (25.0–28.2) | 3,027 | 17.1 (16.4–17.9) | 10,727 |
| 5 | 16.2 (15.4–17.1) | 6,726 | 33.7 (31.6–35.9) | 1,864 | 20.8 (19.9–21.6) | 8,669 |
| 6 | 10.0 (9.4–10.6) | 9,633 | 26.3 (24.7–27.9) | 2,954 | 14.3 (13.6–14.9) | 12,650 |
| 7 | 13.2 (12.5–13.9) | 9,640 | 28.1 (26.4–29.7) | 2,820 | 17.4 (16.7–18.0) | 12,585 |
| 8 | 13.5 (12.9–14.1) | 13,958 | 27.6 (26.2–29.0) | 4,022 | 17.9 (17.3–18.4) | 18,249 |
| 9 | 14.1 (13.5–14.9) | 9,659 | 30.1 (28.4–31.9) | 2,753 | 18.8 (18.1–19.4) | 12,575 |
| 10 | 14.1 (12.9–15.5) | 2,878 | 29.1 (26.3–32.2) | 947 | 18.4 (17.2–19.7) | 3,851 |
| 11 | 9.7 (9.0–10.5) | 5,975 | 23.5 (21.4–25.7) | 1,512 | 13.3 (12.5–14.1) | 7,554 |
| 12 | 14.4 (12.9–16.0) | 2,040 | 28.1 (24.7–31.7) | 661 | 18.4 (16.0–19.9) | 2,721 |
| 13 | 12.1 (10.9–13.2) | 3,151 | 26.5 (24.1–29.1) | 1,245 | 17.3 (16.2–18.4) | 4,456 |
| 14 | 14.5 (12.3–16.9) | 938 | 35.9 (30.2–41.8) | 276 | 19.6 (17.4–22.0) | 1218 |
| Provincial rate | 12.6 (12.3–12.8) | 82,920 | 27.4 (26.9–27.9) | 26,302 | 17.0 (16.7–17.2) | 110,295 |
Abbreviations: BORN, Better Outcomes and Registry Network; CI, confidence interval; LHIN, Local Health Integration Network.
The cohort included women aged 20–34 years with no maternal medical or obstetrical problems and without the following indications for caesarean delivery: cord prolapse, diabetes, fetal anomaly, placental abruption, placenta previa, pre-eclampsia, or other fetal or maternal health problems.
Source: BORN Ontario, mothers who delivered in hospital. (42)
PCMCH Level of Care
Caesarean delivery rates by PCMCH level of care for hospitals showed very little variation. Level 1 hospital rates were slightly higher than the provincial rate and level 2 hospital rates were slightly lower than the provincial rate. The variation was consistent for rates within Robson groups and for the entire cohort. Even though variations were statistically significant, the expert panel did not consider them to be clinically important (Table 22).
Table 22:
Caesarean Delivery Rates for Robson Groups 1 and 2a in a Very-Low-Risk Cohorta by PCMCH Level of Care (2007/2008–2011/2012)
| PCMCH Level of Care | Robson 1 | Robson 2a | Combined (1, 2a, 2b) | |||
|---|---|---|---|---|---|---|
| % (95% CI) | N | % (95% CI) | N | % (95% CI) | N | |
| 1 | 14.8 (14.1–15.4) | 12,001 | 31.9 (30.5–33.3) | 4,297 | 20.0 (19.4–20.7) | 16,450 |
| 2 | 11.6 (11.2–11.9) | 34,887 | 25.3 (24.5–26.2) | 10,443 | 15.5 (15.2–15.8) | 45,742 |
| 2+ | 12.9 (12.5–13.4) | 23,477 | 27.8 (26.8–28.9) | 7,144 | 17.3 (16.9–17.8) | 30,964 |
| Modified 3 | 12.1 (11.2–13.0) | 4982 | 27.7 (25.7–29.7) | 1,964 | 17.3 (16.5–18.2) | 7,019 |
| 3 | 12.8 (12.1–13.6) | 7572 | 26.9 (25.2–28.7) | 2,454 | 17.1 (16.3–17.8) | 10,119 |
| Provincial rate | 12.6 (12.3–12.8) | 82,919 | 27.4 (26.9–27.9) | 26,302 | 17.0 (16.7–17.2) | 110,294 |
Abbreviations: BORN, Better Outcomes and Registry Network; CI, confidence interval; PCMCH, Provincial Centre for Maternal-Child Health.
The cohort included women aged 20–34 years with no maternal medical or obstetrical problems and without the following indications for caesarean delivery: cord prolapse, diabetes, fetal anomaly, placental abruption, placenta previa, pre-eclampsia, or other fetal or maternal health problems.
Source: BORN Ontario, mothers who delivered in hospital. (42)
Hospital Birth Volume
Caesarean delivery rates by hospital birth volume were also compared, and findings suggested that there was variation by birth volume, but only in lower-volume hospitals. When reviewing caesarean delivery rates for hospitals with volumes of less than 500 (≤ 100, 101–250, 251–500), there was a stepwise increase in rates as hospital birth volumes rose, and a comparison of confidence intervals suggested that rates differed. However, for hospitals with birth volumes of > 500 deliveries a year, there was no difference in caesarean delivery rates (Table 23).
Table 23:
Caesarean Delivery Rates for Robson Groups 1 and 2a in a Very-Low-Risk Cohorta by Birth Volume (2007/2008–2011/2012)
| Group | Robson 1 | Robson 2a | Combined (1, 2a, 2b) | |||
|---|---|---|---|---|---|---|
| % (95% CI) | N | % (95% CI) | N | % (95% CI) | N | |
| ≤ 100 | 7.6 (5.1–10.8) | 367 | 30.8 (22.1–40.6) | 104 | 14.0 (11.0–17.5) | 478 |
| 101–250 | 13.6 (11.0–16.5) | 627 | 32.9 (25.9–40.6) | 167 | 18.3 (15.6–21.1) | 800 |
| 251–500 | 18.2 (16.9–19.5) | 3,300 | 37.8 (34.8–40.8) | 1,017 | 23.4 (22.1–24.7) | 4,350 |
| 501–1000 | 12.8 (12.1–13.5) | 8,286 | 26.3 (24.8–27.8) | 3,284 | 17.4 (16.7–18.1) | 11,678 |
| 1001–2,499 | 11.9 (11.4–12.3) | 21,119 | 26.7 (25.7–27.7) | 7,455 | 16.5 (16.1–16.9) | 28,832 |
| 2,500–4,000 | 12.9 (12.5–13.3) | 27,414 | 26.9 (25.9–27.9) | 7,955 | 16.9 (16.5–17.3) | 35,715 |
| 4,000+ | 11.9 (11.5–12.3) | 21,804 | 27.6 (26.5–28.7) | 6,320 | 16.4 (15.9–16.8) | 28,439 |
| Provincial rate | 12.6 (12.3–12.8) | 82,917 | 27.4 (26.9–27.9) | 26,302 | 17.0 (16.7–17.2) | 110,292 |
Abbreviations: BORN, Better Outcomes and Registry Network; CI, confidence interval.
The cohort included women aged 20–34 years with no maternal medical or obstetrical problems and without the following indications for caesarean delivery: cord prolapse, diabetes, fetal anomaly, placental abruption, placenta previa, pre-eclampsia, or other fetal or maternal health problems.
Source: BORN Ontario, mothers who delivered in hospital. (42)
Hospital
Hospital-specific data within PCMCH level-of-care classifications and birth volumes were compared to see if differences in hospital-specific rates could be attributed to either of these factors. The intention was to determine whether there was significant variation in caesarean delivery rates across the province and not necessarily to identify hospitals with high and low rates; a number was assigned to each hospital to avoid naming them.
Hospital-specific rates ranged from 4.5% to 35.5%, and there were no obvious clusters by PCMCH level of care or birth volume (Figures 2 and 3).
Figure 2: Caesarean Delivery Rate for a Very-Low-Risk Cohort of Ontario Women Who Delivered in Hospital, by Hospital and PCMCH Level of Care (2007/2008–2011/2012)a.
Abbreviations: BORN, Better Outcomes and Registry Network; CD, caesarean delivery; PCMCH, Provincial Centre for Maternal-Child Health.
Source: BORN Ontario, mothers who delivered in hospital. (42)
Figure 3: Caesarean Delivery Rate for a Very-Low-Risk Cohort of Ontario Women Who Delivered in Hospital, by Hospital and Birth Volume (2007/2008–2011/2012)a.
Abbreviations: BORN, Better Outcomes and Registry Network.
Source: BORN Ontario, mothers who delivered in hospital. (42)
Within PCMCH levels of care, there was wide variation between hospitals, suggesting that the hospital-specific variation across Ontario was not associated with level of care. This was true for all levels of care, but the differences were most pronounced at the lowest levels of care. The range from highest to lowest were as follows: level 1 hospitals, 5.2% to 35.5%; level 2 hospitals, 4.5% to 25.9%; level 2+ hospitals, 13.6% to 21.5%; modified level 3 hospitals, 14.9% to 18.7%; and level 3 hospitals, 6.3% to 21.7%.
Within birth volumes, there was a similarly striking variation in caesarean delivery rates between hospitals, again suggesting that hospital-specific variation was not due to factors related to birth volumes, such as experience or processes. This was true for all groupings of birth volumes. The range from the highest to lowest rates were as follows: hospitals with < 500 deliveries, 5.2% to 35.5%; hospitals with 501 to 2,499 deliveries, 4.8% to 28.8%; hospitals with 2,500 to 4,000 deliveries, 6.3% to 21.7%; hospitals with > 4,000 deliveries, 4.5% to 21.5%.
Panel Recommendations
After considering the evidence, the Expert Advisory Panel on Rate Variation in Caesarean Sections Across Ontario proposed the following recommendations for the consideration of the Ontario Health Technology Advisory Committee (OHTAC):
Health Quality Ontario, along with key partners, ought to develop and standardize a provincial elective induction policy for low-risk women.
The province should adopt a provincial standard in the caesarean delivery rate for low-risk women equal to a 20% relative decrease in the current provincial rate of 17.0%.
Data from the BORN registry ought to be available to hospitals for audit and quality-improvement initiatives to achieve the planned provincial standard rate for caesarean delivery in low-risk populations.
BORN, along with PCMCH, ought to provide audit and feedback to hospitals regarding their low-risk obstetrical population to support quality improvement in maternal-infant care.
LHINs ought to establish perinatal networks to support the management of labour and delivery in low-risk populations.
As part of its public reporting function, Health Quality Ontario ought to report annually on key performance indicators, including caesarean delivery and induction rates in low-risk women.
CONCLUSIONS
Nine factors were significantly associated with either an increased or decreased likelihood of having a caesarean delivery, and 5 factors had no influence. Moderate-quality evidence supported the finding that in a low-risk population, an elective induction policy would significantly reduce the rate of caesarean deliveries compared with a policy of expectant management.
The provincial caesarean delivery rate for a very-low-risk population was 17.0%. However, rates varied among Ontario hospitals (4.5% to 35.5%) and were independent of PCMCH level-of-care classifications or birth volumes (based on data for 2011/2012).
An evaluation of an Ontario administrative database suggested that variation in caesarean delivery rates may be due to maternal age and/or obstetrical practice variation. There was no clinically or statistically significant variation in rates associated with neighbourhood income quintile, neighbourhood educational attainment, rural or urban status, or primary language.
EXISTING GUIDELINES FOR TECHNOLOGY
We searched the National Guideline Clearinghouse Registry (www.guidelines.ca) for grey literature that reported on factors affecting the likelihood of having a caesarean delivery. Search terms were “caesarean and cesarean,” “caesarean section,” and “cesarean section.” The search returned 49 possible reports, of which 1 was relevant. A systematic review without meta-analysis, completed by the National Institute for Health and Clinical Excellence (NICE), focused on the factors affecting the likelihood of caesarean delivery during intrapartum care. (12)
Table 24 provides a summary of the findings from the NICE systematic review. (12)
Table 24:
Factors Affecting the Likelihood of Having a Caesarean Delivery in Low-Risk Women—NICE Literature Review
| Increases Likelihood | Decreases Likelihood | No Influencea | Further Research Needed | |
|---|---|---|---|---|
| Electronic fetal monitoring | Induction beyond 41 weeks in low-risk pregnancy Continuous support during labour Planned home birth Involvement of a consultant obstetrician in decision-making Partogram with a 4-hour action line | Epidural analgesia Active management | Immersion in water during labour Walking in labour Raspberry leaves Midwifery-led clinic Non-supine position during second stage of labour Early amniotomy | Delayed admission in labour Oxytocin augmentation Parenteral analgesia Complimentary therapies |
Abbreviation: NICE, National Institute for Health and Clinical Excellence.
No statistical difference between treatment (factor) and comparator.
ACKNOWLEDGEMENTS
Editorial Staff
Jeanne McKane, CPE, ELS(D)
Medical Information Services
Corinne Holubowich, Bed, MLIS
Kellee Kaulback, BA(H), MISt
Expert Advisory Panel on Rate Variation in Caesarean Sections Across Ontario
| Panel Members | Affiliation(s) | Appointment(s) |
|---|---|---|
| Co-Chairs | ||
| Pat Campbell | Ontario Hospital Association | President and CEO |
| Dr. Lorraine Ferris | Dalla Lana School of Public Health, University of Toronto | Professor |
| Obstetrician | ||
| Dr. George Arnold | Markham Stouffville Hospital | Chief of Obstetrics and Gynaecology |
| Dr. Nicholas Braithwaite | — | — |
| Dr. Henry Fairley | Thunder Bay Regional Health Sciences Centre | Chief of Obstetrics and Gynaecology |
| Dr. Matt Gysler | Trillium Health Partners | — |
| Dr. Glasine Lawson | Stevenson Memorial Hospital | Chief of Obstetrics and Gynaecology |
| Dr. Nick Leyland | Hamilton Health Sciences McMaster University Medical Centre | Chief/Chair of Department of Obstetrics and Gynaecology |
| Dr. Maxine Lingurar | Sault Area Hospital | Chief of Obstetrics and Gynaecology |
| Dr. Matt Sermer | University of Toronto Mount Sinai Hospital | Professor of Obstetrics and Gynaecology Chief of Obstetrics and Gynaecology |
| Dr. Mark Walker | University of Ottawa Better Outcomes Registry & Network (BORN) | — |
| Dr. Kim Warwick | — | — |
| Researcher | ||
| Dr. Ivy-Lynn Bourgeault | University of Ottawa | Professor and CIHR/Health Canada Research Chair in Health Human Resource Policy |
| Dr. Christine Kurtz Landy | York University | Assistant Professor, Faculty of Health |
| Registered Midwife | ||
| Vicki Van Wagner | Ryerson University | Associate Professor |
| Obstetrical Anesthesiologist | ||
| Dr. Pam Angle | Sunnybrook Health Sciences Centre | Director, Obstetrical Anesthesia Research Unit |
| Dr. Sandra Katsiris | London Health Sciences Centre St. Joseph's Health Care London, Western University | Director of Obstetrical Anesthesia Associate Professor |
| Obstetrical Nurse | ||
| Kate Godwin | Markham Stouffville Hospital | — |
| Marie-Josée Trépanier | Champlain Maternal Newborn Regional Program (CMNRP) | Regional Director |
| Nancy Watts | Canadian Association of Perinatal and Women's Health Nurses (CAPWHN) London Health Sciences Centre | President, CAPWHN Clinical Nurse Specialist, Women's Care Program, LHSC |
| Obstetrician/CEO | ||
| Dr. Jennifer Blake | Society of Obstetricians and Gynaecologists of Canada (SOGC) | CEO |
| CEO | ||
| Michael Barrett | South West Local Health Integration Network | CEO |
| Janet Beed | Markham Stouffville Hospital | President and CEO |
| Executive Director | ||
| Marilyn Booth | Provincial Council for Maternal and Child Health | Executive Director |
| Prenatal Educator | ||
| Virginia Collins | The Childbirth Experience | Childbirth Educator |
| Lisa Keenan-Lindsay | Seneca College of Applied Arts and Technology OPHA Supporting Normal Birth Workgroup | Professor of Nursing |
| Ministry of Health and Long-Term Care Representative | ||
| Wendy Katherine | MOHLTC, Health System Strategy and Policy Division | Manager, Women's and Family Health |
APPENDICES
Appendix 1: Literature Search Strategies
Search date: February 4, 2013
Databases searched: OVID MEDLINE, MEDLINE In-Process and Other Non-Indexed Citations, EMBASE; CINAHL; Cochrane Library; CRD
Q: What are the factors associated with Caesarean section procedures?
Limits: 2008–current; English
Filters: Case reports, editorials, letters, comments, conference abstracts
Database: Ovid MEDLINE(R) 〈1946 to January Week 4 2013〉, Ovid MEDLINE(R) In-Process & Other Non-Indexed Citations 〈February 1, 2013〉, Embase 〈1980 to 2013 Week 05〉 Search Strategy:
| # | Searches | Results |
|---|---|---|
| 1 | exp Cesarean Section/ | 87437 |
| 2 | (c?esarean section∗ or c?section∗ or c section∗ or abdominal deliver∗).ti,ab. | 68893 |
| 3 | or/1–2 | 109225 |
| 4 | exp Patient Satisfaction/ | 131833 |
| 5 | exp Consumer Satisfaction/ use mesz | 71057 |
| 6 | exp patient attitude/ use emez | 224440 |
| 7 | exp consumer attitude/ use emez | 1040 |
| 8 | exp Attitude to Health/ | 340481 |
| 9 | exp Decision Making/ | 234421 |
| 10 | exp “Health Services Needs and Demand”/ use mesz | 43429 |
| 11 | exp Motivation/ | 180799 |
| 12 | exp “Patient Acceptance of Health Care”/ use mesz | 148557 |
| 13 | ((prefer∗ or satisf∗ or request∗) adj4 (Wom?n or patient∗ or matern∗ or mother∗)).ti,ab. | 147336 |
| 14 | ((birth∗ or deliver∗ or c?esarean or c-section∗ or maternal) adj3 prefer∗).ti,ab. | 2875 |
| 15 | exp risk factors/ use mesz or exp risk factor/ use emez | 1059539 |
| 16 | exp Unnecessary Procedures/ use mesz or exp unnecessary procedure/ use emez | 4474 |
| 17 | (risk∗ adj4 (factor∗ or relativ∗ or assess∗ or ratio∗)).ti,ab. | 963104 |
| 18 | or/4–17 | 2555623 |
| 19 | 3 and 18 | 17683 |
| 20 | Meta Analysis.pt. | 36886 |
| 21 | Meta Analysis/ use emez | 68767 |
| 22 | Systematic Review/ use emez | 57104 |
| 23 | exp Technology Assessment, Biomedical/ use mesz | 8789 |
| 24 | Biomedical Technology Assessment/ use emez | 11437 |
| 25 | (meta analy∗ or metaanaly∗ or pooled analysis or (systematic∗ adj2 review∗) or published studies or published literature or medline or embase or data synthesis or data extraction or cochrane).ti,ab. | 301403 |
| 26 | ((health technolog∗ or biomedical technolog∗) adj2 assess∗).ti,ab. | 3938 |
| 27 | or/20–26 | 361998 |
| 28 | 19 and 27 | 975 |
| 29 | limit 28 to english language | 932 |
| 30 | limit 29 to yr=“2008 -Current” | 476 |
| 31 | exp Case Reports/ use mesz or exp case report/ use emez | 3476367 |
| 32 | exp editorial/ or exp comment/ or exp congresses/ or exp letter/ | 2778464 |
| 33 | or/31–32 | 5917490 |
| 34 | 30 not 33 | 465 |
| 35 | remove duplicates from 34 | 310 |
CINAHL
| # | Query | Limiters/Expanders | Results |
|---|---|---|---|
| S1 | (MH “Cesarean Section+”) | Search modes – Boolean/Phrase | 8,916 |
| S2 | (cesarean section∗ caesarean section or c-section∗ or c section∗ or abdominal deliver∗) | Search modes – Boolean/Phrase | 507 |
| S3 | S1 OR S2 | Search modes – Boolean/Phrase | 9,179 |
| S4 | (MH “Consumer Satisfaction+”) | Search modes – Boolean/Phrase | 36,727 |
| S5 | (MH “Patient Attitudes”) | Search modes – Boolean/Phrase | 21,200 |
| S6 | (MH “Consumer Attitudes”) | Search modes – Boolean/Phrase | 3,466 |
| S7 | (MH “Attitude to Health+”) | Search modes – Boolean/Phrase | 81,778 |
| S8 | (MH “Decision Making+”) | Search modes – Boolean/Phrase | 57,927 |
| S9 | (MH “Health Services Needs and Demand+”) | Search modes – Boolean/Phrase | 14,399 |
| S10 | (MH “Motivation+”) | Search modes – Boolean/Phrase | 45,696 |
| S11 | (prefer∗ or satisf∗ or request∗) N4 (Women∗ or woman∗ or patient∗ or matern∗ or mother∗) | Search modes – Boolean/Phrase | 39,793 |
| S12 | ((birth∗ or deliver∗ or cesarean∗ or caesarean∗ or c-section∗ or c section∗ or maternal) N3 prefer∗) | Search modes – Boolean/Phrase | 370 |
| S13 | (MH “Risk Factors+”) | Search modes – Boolean/Phrase | 94,761 |
| S14 | (risk∗ N4 (factor∗ or relativ∗ or assess∗ or ratio∗)) | Search modes – Boolean/Phrase | 247,170 |
| S15 | (MH “Unnecessary Procedures”) | Search modes – Boolean/Phrase | 1,204 |
| S16 | S4 OR S5 OR S6 OR S7 OR S8 OR S9 OR S10 OR S11 OR S12 OR S13 OR S14 OR S15 | Search modes – Boolean/Phrase | 455,562 |
| S17 | S3 AND S16 | Search modes – Boolean/Phrase | 2,323 |
| S18 | (MH “Meta Analysis”) or (MH “Systematic Review”) | Search modes – Boolean/Phrase | 28,113 |
| S19 | ((health technology N2 assess∗) or meta analy∗ or metaanaly∗ or pooled analysis or (systematic∗ N2 review∗) or published studies or medline or embase or data synthesis or data extraction or cochrane) | Search modes – Boolean/Phrase | 64,316 |
| S20 | S18 OR S19 | Search modes – Boolean/Phrase | 64,316 |
| S21 | S17 AND S20 | Search modes – Boolean/Phrase | 137 |
| S22 | S17 AND S20 | Limiters – Published Date from: 20080101–20131231; English Language Search modes – Boolean/Phrase | 79 |
Cochrane
| ID | Search | Hits |
|---|---|---|
| #1 | MeSH descriptor: [Cesarean Section] explode all trees | 2144 |
| #2 | c?esarean section∗ or c?section∗ or c section∗ or abdominal deliver∗:ti (Word variations have been searched) | 1069 |
| #3 | #1 or #2 | 2704 |
| #4 | MeSH descriptor: [Patient Satisfaction] explode all trees | 7582 |
| #5 | MeSH descriptor: [Consumer Satisfaction] explode all trees | 8155 |
| #6 | MeSH descriptor: [Attitude to Health] explode all trees | 20987 |
| #7 | MeSH descriptor: [Decision Making] explode all trees | 2134 |
| #8 | MeSH descriptor: [Health Services Needs and Demand] explode all trees | 352 |
| #9 | MeSH descriptor: [Motivation] explode all trees | 4229 |
| #10 | MeSH descriptor: [Patient Acceptance of Health Care] explode all trees | 16765 |
| #11 | ((prefer∗ or satisf∗ or request∗) near/4 (Wom?n or patient∗ or matern∗ or mother∗)):ti (Word variations have been searched) | 1233 |
| #12 | ((birth∗ or deliver∗ or c?esarean or c-section∗ or maternal) near/3 prefer∗):ti (Word variations have been searched) | 10 |
| #13 | MeSH descriptor: [Risk Factors] explode all trees | 16429 |
| #14 | MeSH descriptor: [Unnecessary Procedures] explode all trees | 81 |
| #15 | (risk∗ near/4 (factor∗ or relativ∗ or assess∗ or ratio∗)):ti (Word variations have been searched) | 2986 |
| #16 | #4 or #5 or #6 or #7 or #8 or #9 or #10 or #11 or #12 or #13 or #14 or #15 | 43506 |
| #17 | #3 and #16 from 2008 to 2013 | 64 |
CRD
| Line | Search | Hits |
|---|---|---|
| 1 | MeSH DESCRIPTOR Cesarean Section EXPLODE ALL TREES | 145 |
| 2 | (c?esarean section∗ or c?section∗ or c section∗ or abdominal deliver∗):TI | 94 |
| 3 | #1 OR #2 | 205 |
| 4 | MeSH DESCRIPTOR Patient Satisfaction EXPLODE ALL TREES | 623 |
| 5 | MeSH DESCRIPTOR Consumer Satisfaction EXPLODE ALL TREES | 645 |
| 6 | MeSH DESCRIPTOR Attitude to Health EXPLODE ALL TREES | 1524 |
| 7 | MeSH DESCRIPTOR Decision Making EXPLODE ALL TREES | 254 |
| 8 | MeSH DESCRIPTOR Health Services Needs and Demand EXPLODE ALL TREES | 92 |
| 9 | MeSH DESCRIPTOR Motivation EXPLODE ALL TREES | 110 |
| 10 | MeSH DESCRIPTOR Patient Acceptance of Health Care EXPLODE ALL TREES | 1217 |
| 11 | ((prefer∗ or satisf∗ or request∗) adj4 (Wom?n or patient∗ or matern∗ or mother∗)):TI | 6 |
| 12 | ((birth∗ or deliver∗ or c?esarean or c-section∗ or maternal) adj3 prefer∗):TI | 0 |
| 13 | MeSH DESCRIPTOR risk factors EXPLODE ALL TREES | 2020 |
| 14 | MeSH DESCRIPTOR unnecessary procedures EXPLODE ALL TREES | 16 |
| 15 | (risk∗ adj4 (factor∗ or relativ∗ or assess∗ or ratio∗)):TI | 159 |
| 16 | #4 OR #5 OR #6 OR #7 OR #8 OR #9 OR #10 OR #11 OR #12 OR #13 OR #14 OR #15 3890 | |
| 17 | #3 AND #16 | 37 |
| 18 | (#17):TI FROM 2008 TO 2013 | 13 |
Appendix 2: Evidence Quality Assessment
Table A1:
AMSTAR, Scores of Included Systematic Reviews
| Author, Year | AMSTAR Score | (1) Provided Study Design | (2) Duplicate Study Selection | (3) Broad Literature Search | (4) Considered Status of Publication | (5) Listed Excluded Studies | (6) Provided Characteristics of Studies | (7) Assessed Scientific Quality | (8) Considered Quality in Report | (9) Methods to Combine Appropriate | (10) Assessed Publication Bias | (11) Stated Conflict of Interest |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Gulmezoglu et al, 2012 (26) | 11 | ✓ | ✓ | ✓ | ✓ | ✓ | ✓ | ✓ | ✓ | ✓ | ✓ | ✓ |
| Anim-Somuah et al, 2011 (21) | 10 | ✓ | ✓ | ✓ | ✓ | ✓ | ✓ | ✓ | ✓ | ✓ | ˟ | ✓ |
| O'Mahony et al, 2010 (30) | 10 | ✓ | ✓ | ✓ | ✓ | ✓ | ✓ | ✓ | ✓ | ✓ | ˟ | ✓ |
| Devane et al, 2012 (25) | 10 | ✓ | ✓ | ✓ | ✓ | ✓ | ✓ | ✓ | ✓ | ✓ | ˟ | ✓ |
| Lavender et al, 2012 (27) | 10 | ✓ | ✓ | ✓ | ✓ | ✓ | ✓ | ✓ | ✓ | ✓ | ˟ | ✓ |
| Brown et al, 2008 (23) | 10 | ✓ | ✓ | ✓ | ✓ | ✓ | ✓ | ✓ | ✓ | ✓ | ˟ | ✓ |
| Bugg et al, 2011 (24) | 10 | ✓ | ✓ | ✓ | ✓ | ✓ | ✓ | ✓ | ✓ | ✓ | ˟ | ✓ |
| Wendland et al, 2012 (34) | 9 | ✓ | ✓ | ✓ | ˟ | ✓ | ✓ | ✓ | ˟ | ✓ | ✓ | ✓ |
| Middleton et al, 2012 (29) | 10 | ✓ | ✓ | ✓ | ✓ | ✓ | ✓ | ✓ | ✓ | ✓ | ˟ | ✓ |
| Bayrampour and Heaman, 2010 (22) | 6 | ✓ | ˟ | ✓ | ˟ | ✓ | ˟ | ✓ | ✓ | ✓ | ˟ | ˟ |
| Mazzoni et al, 2011 (28) | 8 | ✓ | ✓ | ✓ | ✓ | ˟ | ✓ | ✓ | ˟ | ✓ | ˟ | ✓ |
| Poobalan et al, 2009 (32) | 7 | ✓ | ✓ | ✓ | ˟ | ˟ | ˟ | ✓ | ✓ | ✓ | ˟ | ✓ |
| Pandey et al, 2012 (31) | 9 | ✓ | ✓ | ✓ | ˟ | ✓ | ✓ | ✓ | ✓ | ˟ | ✓ | ✓ |
| Ruiz-Mirazo et al, 2012 (33) | 7 | ✓ | ✓ | ✓ | ˟ | ˟ | ✓ | ✓ | ✓ | ✓ | NA | ˟ |
Abbreviations: AMSTAR, Assessment of Multiple Systematic Reviews; NA, not applicable.
Maximum possible score is 11. Details of AMSTAR score are described in Shea et al. (19)
Table A2:
GRADE Evidence Profile for Labour Induction Policy
| No. of Studies (Design) | Risk of Bias | Inconsistency | Indirectness | Imprecision | Publication Bias | Upgrade Considerations | Quality |
|---|---|---|---|---|---|---|---|
| Caesarean Delivery | |||||||
| 21 RCTs (44–64) | Seriousa limitations | No serious limitations | No serious limitations | No serious limitations | Undetectedb | None | ⊕⊕⊕ Moderate |
| Subgroup 37–39 Weeks | |||||||
| 1 RCT (46) | No serious limitations | Not applicable | No serious limitations | Serious limitationsc | Likelyd | None | ⊕⊕ Low |
| Subgroup 39–40 Weeks | |||||||
| 3 RCTs (49;51;60) | Serious lImitationse | No serious limitations | No serious limitations | Serious limitationsc | Undetected | None | ⊕ ⊕ Low |
| Subgroup < 41 Weeks | |||||||
| 1 RCT (47) | Serious limitationsf | Not applicable | No serious limitations | Serious limitationsc | Likelyd | None | ⊕ Very Low |
| Subgroup 41 Weeks | |||||||
| 4 RCTs (50;52;57;58) | No serious limitations | No serious limitations | No serious limitations | Serious limitationsg | Undetected | None | ⊕ ⊕ ⊕ Moderate |
| Subgroup > 41 Weeks | |||||||
| 12 RCTs (44;45;48;53;54;55;56;59;61–64) | Serious limitationsh | No serious limitations | No serious limitations | No serious limitations | Undetected | None | ⊕ ⊕ ⊕ Moderate |
Abbreviations: GRADE, Grading of Recommendations Assessment, Development and Evaluation; RCT, randomized controlled trial.
Twelve of 21 studies had unclear allocation concealment; the rest had low risk of bias. Outcome assessor was not blinded in all RCTs; caesarean delivery is an objective outcome.
Funnel plot for caesarean delivery had a flattened appearance, and its interpretation was unclear.
Confidence interval included appreciable harms and benefits.
One study retrieved from the literature search.
Two of 3 RCTs had unclear allocation concealment.
Unclear allocation concealment methods.
Optimal information size not met.
Eight of 12 RCTs had unclear allocation concealment methods.
Table A3:
GRADE Evidence Profile for Group Prenatal Care
| No. of Studies (Design) | Risk of Bias | Inconsistency | Indirectness | Imprecision | Publication Bias | Upgrade Considerations | Quality |
|---|---|---|---|---|---|---|---|
| Caesarean Delivery | |||||||
| 1 RCT (39) | Serious limitationsa | Not applicable | Serious limitationsb | No limitations | Undetectedc | None | ⊕ ⊕ Low |
Abbreviations: GRADE, Grading of Recommendations Assessment, Development and Evaluation; RCT, randomized controlled trial.
Cluster randomization study; allocation concealment was not reported.
Study completed in Iran.
One study; difficult to assess publication bias.
Table A4:
Risk of Bias Among Randomized Controlled Trials for Induction Policy
| Author, Year | Allocation Concealment | Blinding | Complete Accounting of Patients and Outcome Events | Selective Reporting Bias | Other Limitations |
|---|---|---|---|---|---|
| Breart et al, 1982 (46) | No limitationsa | Limitationsb | No limitationsa | No limitationsa,c | No limitations |
| Cole et al, 1975 (49) | Limitationsd | Limitationsb | No limitationsa | No limitations | No limitations |
| Egarter et al, 1989 (51) | Limitationsd | Limitationsb | No limitationsa | No limitations | No limitations |
| Nielson et al, 2005 (60) | No limitations | Limitationsb | No limitations | Limitationse | No limitations |
| Chakravarti et al, 2000 (47) | Limitationsd | Limitationsb | No limitations | No limitationsa,f | No limitations |
| Dyson et al, 1987 (50) | No limitationsa | Limitationsb | No limitations | No limitations | No limitations |
| Gelisen et al, 2005 (52) | No limitations | Limitationsb | No limitations | No limitations | No limitations |
| James et al, 2001 (57) | No limitationsa | Limitationsb | No limitations | No limitations | No limitations |
| Martin et al, 1989 (58) | Limitationsg | Limitationsb | No limitations | No limitations | No limitations |
| Augensen et al, 1987 (44) | Limitationsh | Limitationsb | No limitations | No limitations | No limitations |
| Bergsjo et al, 1989 (45) | Limitationsb | Limitationsb | No limitations | Limitationsi | No limitations |
| Chanrachkul et al, 2003 (48) | Limitationsd | Limitationsb | No limitations | No limitations | No limitations |
| Hannah et al, 1992 (53) | No limitations | Limitationsb | No limitations | No limitations | No limitations |
| Heimstad et al, 2007 (54) | No limitations | Limitationsb | No limitations | No limitations | No limitations |
| Henry et al, 1969 (55) | Limitationsd | Limitationsb | No limitations | No limitations | No limitations |
| Herabutya et al, 1992 (56) | Limitationsd | Limitationsb | No limitations | No limitations | No limitations |
| NICHHD, 1994 (59) | No limitations | Limitationsb | No limitations | No limitations | No limitations |
| Ocon et al, 1997 (61) | Limitationsd | Limitationsb | No limitations | No limitations a | No limitations |
| Roach et al, 1997 (62) | Limitationsj | Limitationsb | No limitations | Limitationsk | No limitations |
| Sahraoui et al, 2005 (63) | Limitationsd | Limitationsb | No limitations | No limitations | No limitations |
| Witter et al, 1987 (64) | No limitationsa | Limitationsb | No limitations | Limitationsl | No limitations |
Abbreviation: NICHHD, National Institute of Child Health and Human Development.
Evaluation differed from that of Cochrane review.
Not reported.
Perinatal mortality was not reported.
Method of allocation concealment was not reported.
Perinatal mortality was not reported, and only 3 neonatal outcomes were reported.
No prespecified outcomes.
Allocation was in sealed envelopes, but there was no mention of opaqueness, numbering, or sequential opening of envelope.
Allocation concealment was unclear, given that it was not undertaken by a staff member or team clearly uninvolved in the trial.
Limited information was provided for some outcomes, such as combined maternal complications.
Allocation was in a series of identical envelopes, but there was no mention of sealed envelopes, opaqueness, or sequential numbered envelopes.
Perinatal mortality was not reported.
Perinatal death was not reported.
Table A5:
Risk of Bias Among Randomized Controlled Trials for Group Prenatal Care
| Author, Year | Allocation Concealment | Blinding | Complete Accounting of Patients and Outcome Events | Selective Reporting Bias | Other Limitations |
|---|---|---|---|---|---|
| Jafari et al, 2010 (39) | Limitationsa | No limitations | No limitations | No limitations | No limitations |
Not reported.
Appendix 3: Forest Plot
Figure A1: Group Prenatal Care Compared With Individual Prenatal Care.
Abbreviations: CI, confidence interval; M-H, Mantel-Haenszel.
Footnotes
Care received in an office setting—possibly including induction methods—cannot be captured reliably in hospital records. Some women may have been misclassified as being in spontaneous labour when presenting to hospital after having received some type of induction in a physician's office.
The cohort included women aged 20–34 years with no maternal medical or obstetrical problems and without the following indications for caesarean delivery: cord prolapse, diabetes, fetal anomaly, placental abruption, placenta previa, pre-eclampsia, or other fetal or maternal health problems.
The cohort included women aged 20–34 years with no maternal medical or obstetrical problems and without the following indications for caesarean delivery: cord prolapse, diabetes, fetal anomaly, placental abruption, placenta previa, pre-eclampsia, or other fetal or maternal health problems.
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