Abstract
Introduction and hypothesis
This study describes pelvic organ support after childbirth.
Methods
This ancillary analysis of the Childbirth and Pelvic Symptoms Imaging Study compares pelvic organ prolapse quantification 6–12 months after childbirth among three cohorts of primiparous women: vaginal delivery with sphincter tear (n=106), vaginal delivery without sphincter tear (n=108), and cesarean without labor (n=39).
Results
Of participants, 31.2% had stage II support. Prolapse to or beyond the hymen was present in 14% after vaginal delivery with sphincter tear (95% confidence interval 8%, 22%), 15% (9%, 24%) after vaginal delivery without sphincter tear, and 5% (1%, 17%) after cesarean without labor (p=0.23). A study of 132 women per group would be required for 80% power to test differences between 5% and 15%.
Conclusions
While these data provide insufficient power to dismiss a difference in pelvic organ support between modes of delivery, they add to our understanding of support following childbirth.
Keywords: Pelvic organ prolapse quantification, Uterine prolapse, Childbirth, Cesarean, Obstetrical anal sphincter laceration
Introduction
Pelvic organ prolapse affects a large portion of adult women. Studies suggest that approximately half of women undergoing routine gynecologic examination demonstrate some evidence of prolapse [1, 2]. Epidemiologic studies consistently identify parity as an important risk factor for the development of pelvic organ prolapse [2–5]. However, it is unclear whether this loss of pelvic organ support is attributed to delivery or pregnancy itself. Some studies associate prolapse with pelvic floor injury sustained during vaginal delivery and suggest cesarean delivery may decrease the risk of pelvic organ prolapse [6–8]. Cesarean delivery as a potential prevention strategy remains unproven.
The goal of this study is to describe pelvic organ support 6–12 months after a first vaginal or cesarean delivery. This study is a secondary analysis of data collected for the Childbirth and Pelvic Symptoms Imaging Study (CAPSIS) [9], focusing on the results of structured examinations for pelvic organ support among primiparous women 6–12 months after a first delivery.
Materials and methods
This study is a secondary analysis of data collected for the Childbirth and Pelvic Symptoms (CAPS) Study [10], which was the parent study of CAPSIS [9]. Both of these studies were performed through the Pelvic Floor Disorders Network (PFDN), a cooperative agreement network sponsored by the Eunice Kennedy Shriver National Institute of Child Health and Human Development and the Office of Research on Women’s Health.
CAPS (September 2002–March 2005) [10] was a prospective cohort study of postpartum fecal and urinary incontinence in primiparous women who sustained clinically recognized anal sphincter tears during vaginal delivery. The methods of the CAPS study were previously reported [10]. Three cohorts of women were enrolled immediately postpartum. The primary cohort consisted of primiparous women with a recognized anal sphincter laceration following vaginal delivery. The second cohort consisted of controls with a vaginal delivery not complicated by an anal sphincter laceration. This cohort was recruited from the next consecutive primiparous patient who delivered following a subject enrolled into the laceration cohort. The third cohort consisted of primiparas who underwent a cesarean section without labor. Women were recruited while in the hospital after delivery and interviewed by telephone 6 weeks and 6 months postpartum. Each PFDN institution, including the data-coordinating center at the University of Michigan, received Institutional Review Board (IRB) approval for the protocol and all participants provided written informed consent. The CAPS study enrolled 921 primiparous women: 407 with clinically recognized tear, 390 without recognized tear, and 124 with cesarean before labor.
The CAPS population did not undergo a physical examination, and therefore, pelvic organ support was not documented among the 921 CAPS participants. However, CAPS participants were also invited to join the CAPSIS study, a supplementary study designed to estimate whether symptoms of fecal incontinence are associated with imaging findings, including endoanal ultrasound and magnetic resonance imaging (MRI). The CAPSIS study included a physical examination, with a structured assessment of pelvic organ support. Therefore, we used data from the CAPSIS population to investigate postpartum pelvic organ support in these three cohorts.
The methods of the CAPSIS study were previously published [9]. Subjects in this study were recruited from women enrolled in the CAPSIS study at the final CAPS visit. Separate IRB approval and written informed consent was obtained for this study. The CAPSIS study correlated standardized imaging (MRI and endoanal ultrasound), physical examination findings, including pelvic organ prolapse quantification (POP-Q) [11], and symptom assessment. The planned sample size for the CAPSIS study was 255. Ultimately, 256 women participated in CAPSIS (109 women in the sphincter tear group, 108 in the vaginal control group, and 39 in the cesarean control group).
The analysis reported in this study is a planned secondary analysis of CAPSIS data. Pelvic organ support data for this investigation were obtained from the CAPSIS physical examination, which was performed 6–12 months after delivery and included a structured assessment of pelvic organ support, according to the POP-Q system [11]. Age and race were self-reported at baseline. Body mass index was calculated from measurements of height and weight obtained at the 6–12 month examination. The infants’ birth weights were abstracted from the hospital record.
Descriptive statistics are provided regarding pelvic organ support. For each birth cohort, support was classified by stage (according to the POP-Q system). In addition, we calculated the proportion of women with prolapse to or beyond the hymen. The sample size for this ancillary study was determined based on enrollment into the parent study. We used Fisher exact test to compare the proportions of women with prolapse to or beyond the hymen in the three groups. Finally, for each POP-Q measure, we calculated the median value and standard deviation for each cohort of women.
Results
A total of 256 primiparous subjects were enrolled in CAPSIS. This secondary analysis includes data from 253 women (98.8%). Characteristics of the population are summarized in Table 1. All groups were similar with respect to age, postpartum body mass index (BMI), and race, with the majority being Caucasian. Mean infant birth weight was lower in the vaginal delivery without sphincter tear group as compared to the other cohorts.
Table 1.
Characteristics of 253 primiparous participants
| Vaginal delivery with anal sphincter tear (N=106) | Vaginal delivery without anal sphincter tear (N=108) | Cesarean delivery before labor (N=39) | |
|---|---|---|---|
| Age, years (mean, SD) | 27.6±6.2 | 26.1±5.6 | 28.2±7.4 |
| Postpartum BMI, kg/m2 (mean, SD) | 27.2±6.9 | 26.7±6.2 | 29.3±8.3 |
| Racea | |||
| Caucasian | 79 (76%) | 71 (66%) | 29 (74%) |
| Black | 22 (21%) | 31 (29%) | 9 (23%) |
| Other | 3 (3%) | 6 (6%) | 1 (3%) |
| Infant’s birth weight, grams (mean, SD) | 3593±442 | 3396±367 | 3526±483 |
Two subjects refused to answer the question
Pelvic organ support stage at 6–12 months postpartum is shown in Table 2. Almost one third of participants had stage II support (31.2%). Prolapse beyond the hymen was present in all three cohorts. Specifically, the most dependent point of the vaginal wall was to or beyond the hymen in 15 of 105 of those who delivered vaginally with a sphincter tear (14%; 95% confidence interval (CI) 8%, 22%), 16 of 104 of those who delivered vaginally without a sphincter tear (15%; 95% CI 9%, 24%), and two of 39 of those who delivered by cesarean without labor (5%; 95% CI 1%, 17%). The difference between groups was not significant (p=0.23). In a post hoc analysis, we calculated that a sample of 132 women per group would be required for 80% power to test the difference between 5% and 15% prevalence of prolapse between two groups.
Table 2.
Pelvic organ support, by delivery cohort
| Stage of pelvic organ support | Vaginal delivery with anal sphincter Tear (N=106) | Vaginal delivery without anal sphincter tear (N=108) | Cesarean delivery before labor (N=39) |
|---|---|---|---|
| Stage 0 | 32 (30%) | 23 (22%) | 17 (44%) |
| Stage 1 | 32 (30%) | 51 (49%) | 14 (36%) |
| Stage 2 | 40 (38%) | 30 (29%) | 8 (21%) |
| Stage 3 | 1 (1%) | 0 (0%) | 0 (0%) |
| Missing | 1 | 4 | 0 |
Support is described according to Pelvic Organ Prolapse Quantification Stage
The individual POP-Q measures are shown in Table 3. There is a trend toward poorer support of the anterior vaginal wall in the vaginal delivery cohorts as compared to the cesarean without labor. However, other measures appear to be similar among cohorts.
Table 3.
Pelvic organ support, by delivery cohort
| POP-Q measure (mean, SD) | Vaginal delivery with anal sphincter tear (N=106) | Vaginal delivery without anal sphincter tear (N=108) | Cesarean delivery before labor (N=39) |
|---|---|---|---|
| Aa | −2 (−3, −1) | −2 (−3, −1) | −3 (−3, −2) |
| Ba | −2 (−3, −1) | −2 (−3, −1) | −3 (−3, −2) |
| C | −7 (−8, −6) | −7 (−8, −6) | −8 (−8.5, −6) |
| D | −8 (−9, −7.5) | −8 (−9, −7.5) | −9 (−10, −8) |
| GH, straining | 3 (2, 4) | 3 (2.5, 3) | 2 (1.5, 2.5) |
| GH, at rest | 2 (2, 3) | 2 (2, 3) | 2 (2, 3) |
| PB, straining | 3 (2.5, 3.5) | 3.5 (3, 4) | 2.5 (2, 4) |
| PB, at rest | 3.5 (3, 4) | 3.3 (3, 4) | 3.5 (2.5, 4) |
| Ap | −3 (−3, −2) | −3 (−3, −2) | −3 (−3, −3) |
| Bp | −3 (−3, −2) | −3 (−3, −2) | −3 (−3, −3) |
| TVL | 9 (8, 10) | 9 (8, 10) | 9 (9, 10) |
Support is described in centimeters at each point for the pelvic organ prolapse quantification examination. Data represent median (intraquartile range)
Discussion
In this study, we describe the range of pelvic organ support in three cohorts of postpartum women. Our findings add to the scarce published information about objectively measured pelvic organ prolapse following the first delivery. In a PubMed literature search of publications through December 2008, we found only three manuscripts that objectively quantified prolapse in the first year after the first delivery using the POP-Q system [12–14]. Sze and colleagues [12] found postpartum prolapse, defined as stage II or worse, in 50 women (52%) 6 weeks after delivery. Similarly, O’Boyle and colleagues [13] found stage II support in two thirds of 62 primiparous women examined 5–22 weeks postpartum. We found stage II support in only one third of postpartum women. Thus, our results are somewhat more encouraging with respect to postpartum pelvic organ support. The differences may be due to the timing of the postpartum examination. Women in this study were not examined until they were at least 6 months from delivery and it is possible that a higher proportion of advanced stage pelvic organ support would have been observed earlier in the first year after delivery. Longitudinal studies, describing changes in pelvic organ support during pregnancy and the first year postpartum, would help to clarify the natural history of pelvic organ support related to childbirth.
We also considered pelvic organ support at all measured sites. The most striking finding was the relative absence of anterior vaginal wall prolapse among women who had undergone cesarean without labor. Among 39 women examined, all women had point Aa at least 2 cm above the hymen. In contrast, the median support observed in the other two comparison groups was 2 cm above the hymen, indicating that at least 50% of women delivered vaginally had prolapse beyond that point. It remains to be seen whether these small absolute differences in anterior wall support will translate into clinically meaningful prolapse later in life. It is important to note that we did not observe clinically significant apical prolapse in this population.
Similar to Zhu et al. [14], we observed a low prevalence of prolapse after cesarean delivery. We found prolapse to or beyond the hymen in only 5% of women who had undergone cesarean without labor. The 95% confidence interval for prevalence of prolapse to or beyond the hymen is between 1% and 17%. Thus, cesarean delivery was not completely protective. However, our findings cannot be attributed with certainty to delivery method, since some women may have developed prolapse before delivery or pregnancy and prolapse was not assessed prior to delivery in this population. For example, O’Boyle found that POP-Q stage was higher in the third trimester than first trimester but did not change significantly following delivery [13]. Thus, postpartum changes cannot with certainty be attributed to mode of delivery or intrapartum events. Furthermore, our sample size was not sufficiently large to exclude a significant difference between groups. Our findings argue for larger studies to conclusively study pelvic organ support after childbirth and specifically to address possible differences between cesarean and vaginal birth.
Our study is unique because of the relatively large numbers of participants who underwent cesarean prior to labor and because we examined a large number of women who had sustained obstetrical sphincter tears during labor. Strengths of our study include the objective assessment of prolapse and that examiners were masked to delivery type. While our numbers are too small to allow statistical comparisons among groups, information from our population doubles that currently available in the literature in this area and provides preliminary data that will facilitate the planning of future studies. Specifically, further research would be required to determine whether cesarean delivery before labor reduces the incidence of pelvic organ prolapse and to investigate the prognostic significance of support defects and symptoms noted in the early postpartum period.
Acknowledgments
Supported by grants from the National Institute of Child Health and Human Development (U01 HD41249, U10 HD41268, U10 HD41248, U10 HD41250, U10 HD41261, U10 HD41263, U10 HD41269, and U10 HD41267).
Appendix
Pelvic Floor Disorders Network Members
University of Alabama at Birmingham
Holly E. Richter, Ph.D., M.D., Principal investigator
Kathryn Burgio, Ph.D., Co-principal investigator
Patricia Goode, M.D., Co-investigator
R. Edward Varner, M.D., Co-investigator
Gregg Shore, M.D., Co-investigator
Franklin Tessler, M.D., Co-investigator
Mark Lockhart, M.D., MPH, Co-investigator
Velria Willis, R.N., B.S.N., Research coordinator
Baylor College of Medicine
Paul M. Fine, M.D., Principal investigator
Rodney A. Appell, M.D., Co-principal investigator
Peter K. Thompson, M.D., Co-investigator
Peter M. Lotze, M.D., Co-investigator
Naomi Frierson, Research coordinator
University of Iowa
Ingrid Nygaard, M.D., Principal investigator
Debra Brandt, R.N., Denise Haury, R.N. Research coordinators
Karl Kreder, M.D., Co-investigator
Catherine S. Bradley, M.D., Co-investigator
Satish Rao, M.D., Co-investigator
Johns Hopkins Medical Institutes
Geoffrey Cundiff, M.D., Principal investigator
Victoria Handa, M.D., Co-investigator
Mary Elizabeth Sauter, N.P., Research coordinator
Jamie Wright, M.D., Co-investigator
Loyola University, Chicago
Linda Brubaker, M.D., Principal investigator
Mary Pat FitzGerald, M.D., Co-principal investigator
Kimberly Kenton, M.D., Co-investigator
Dorothea Koch, R.N., Research coordinator
Charity Ball, R.N., Research coordinator
University of Michigan
Morton B. Brown, Ph.D., Principal investigator
John T. Wei, M.D., M.S., Co-principal investigator
Beverly Marchant, RN, BS, Project manager
John O.L. DeLancey, M.D., Co-investigator
Nancy K. Janz, Ph.D., Co-investigator
Dean G. Smith, Ph.D., Co-investigator
Patricia A. Wren, Ph.D., Co-investigator
Wen Ye, PhD, Statistician
James Imus, MS, Statistician
Yang Wang Casher, MS, Database programmer
University of North Carolina at Chapel Hill
Anthony G. Visco, M.D., Principal investigator
AnnaMarie Connolly, M.D., Co-investigator
John Lavelle, M.D., Co-investigator
Mary J. Loomis, R.N., Research coordinator
Anita K. Murphy, N.P., Research coordinator
Ellen C. Wells, M.D., Co-investigator
William Whitehead, Ph.D., Co-investigator
Julia Fielding, M.D., Co-investigator
University of Pittsburgh/Magee-Womens Hospitals
Halina Zyczynski, M.D., Principal investigator
Diane Borello-France, Ph.D., Co-investigator
Christiane Hakim, M.D., Co-investigator
Arnold Wald, M.D., Co-investigator
Judy A. Gruss, B.S., M.S., Research coordinator
Wendy Leng, M.D., Co-investigator
Pamela A. Moalli, M.D., Ph.D., Co-investigator
Steering Committee Chairman
Robert Park, M.D.
NICHD Project Scientist
Anne M. Weber, M.D., M.S.
Footnotes
Conflicts of interest Dr. Kenton serves as a consultant for Pfizer; the remaining authors have no conflicts of interest.
Contributor Information
Victoria L. Handa, Email: vhanda1@jhmi.edu, Department of Gynecology & Obstetrics, Johns Hopkins University, 4940 Eastern Avenue, Baltimore, MD 21224, USA
Ingrid Nygaard, University of Utah, Salt Lake City, UT, USA.
Kimberly Kenton, Loyola University, Maywood, IL, USA.
Geoffrey W. Cundiff, University of British Columbia, Vancouver, BC, Canada
Chiara Ghetti, University of Pittsburgh, Pittsburgh, PA, USA.
Wen Ye, University of Michigan, Ann Arbor, MI, USA.
Holly E. Richter, University of Alabama at Birmingham, Birmingham, AL, USA
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