Table 1. Included randomised controlled trials and meta-analyses of trials.
| Author, Publication year | Indication | Study design | Country and Setting | Aim and Participants | Main Findings | Risk of bias |
|---|---|---|---|---|---|---|
| Gurung et al. (2013) [163] | Cholestasis | A Cochrane review of randomised and quasi randomised controlled trials | UK. While this review identified 21 RCTs for inclusion, only one RCT is relevant to our review and compared outcomes for early term delivery versus EM (the PITCH 2012 trial in the UK) and the findings of this study are reported here (N = 63) | N = 63 To evaluate the effectiveness and safety of interventions in women with cholestasis of pregnancy. Includes one RCT that compared outcomes for early term birth (n = 30) (IOL between 37+0 and 37+6) versus EM (n = 33). | There were no stillbirths or neonatal deaths in either group and no significant differences in CS (RR 0.68), passage of meconium-stained liquor (RR 0.55) or admission to NICU (RR 0.55). | Low |
| Boulvain et al. (2009) [145] | Diabetes (either type I or type II), or GDM | Cochrane review of RCTs | 1 RCT included. Setting not specified in Cochrane review. | N = 200 To compare outcomes for IOL (n = 100) versus EM (n = 100) at term (≥38 weeks) for diabetic (either type I or type II, or GDM) pregnant women treated with insulin. Women with other complications were excluded. | No significant differences between the two groups in terms of CS (RR 0.81), the risk of macrosomia was reduced in the IOL group (RR 0.56) and three cases of mild shoulder dystocia were reported in the EM group. No other perinatal morbidity was reported. | Low |
| Biesty et al. (2018) [9] | Diabetes—GDM | Cochrane review of RCTs | 1 RCT included. Multi-centre study conducted between 2010 and 2014, with teaching hospitals from Italy, Slovenia and Israel. | N = 425 To evaluate maternal and perinatal outcomes after IOL (n = 214) versus EM (n = 211) in pregnant women with GDM at term (included trial enrolled women at 38–39 weeks, excluded if estimated fetal weight over 4kg). Women with other complications (including diabetes type I or II) and previous CS were excluded. | No significant difference between the two groups in terms of CS rates (RR 1.06; 12.6% in the IOL group versus 11.7% in the expectant group), or other maternal or neonatal outcomes. | Low |
| Sutton et al. (2014) [146] | Diabetes—GDM | Secondary analysis of an RCT that compared different treatments for mild GDM. | Hospitals in North America that are members of the NICHD Maternal-Fetal Medicine Units Network | N = 679 (of the original 958 women) To compare CS rates associated with IOL (n = 220) versus EM (n = 459). | IOL was not associated with increased rates of CS at 37, 38, or 39 weeks, but was associated with a 3-fold increase in CS rates at 40 weeks and beyond. | Low |
| Grant et al. (2013) [182] | Gastrochisis | A Cochrane review of RCTs; studies with quasi randomised design or cross-over design were excluded | UK. Single centre RCT conducted between May 1995 and September 1999 | N = 42 To assess the effects of planned preterm birth (< 37 weeks) for fetal gastroschisis by comparing outcomes for IOL at 36 weeks (n = 21) and spontaneous onset of labour (n = 21) | There was no significant benefit or adverse effect associated with elective preterm birth, but the included trial was underpowered to detect clinically important outcome differences. | Low |
| Amorim et al. (2017) [120] | Hypertension—Severe preeclampsia | Cochrane review of RCTs; quasi RCTs or studies with cross-over design were excluded | No studies identified for inclusion. | To compare planned CS versus IOL for severe preeclampsia | No studies identified for inclusion. | No included studies |
| Chappell et al. (2019) [122] | Preeclampsia between 34–37 weeks | RCT | England and Wales. Multi-site including 46 maternity units | N = 901 To compare planned birth (usually IOL) (n = 448) versus EM (n = 338) in women with late preterm pre-eclampsia from 34 to 37 weeks and a singleton or dichorionic diamniotic twin pregnancy. | Planned birth reduced maternal morbidity and severe hypertension (65% vs 75%, RR = 0.86, 95% CI 0·79–0·94; p = 0·0005), but more neonatal admissions for prematurity (42% vs 34%, RR 1·26, 1·08–1·47; p = 0·0034) | Low |
| Churchill et al. (2013)† [119] | Hypertension—Severe preeclampsia between 24 and 34 weeks | Cochrane review of RCTs; quasi randomised studies were excluded | 4 included RCTs from Europe, USA and South Africa | N = 425 To compere planned early birth (by IOL or CS) (n = 222) versus EM (n = 203) | An expectant approach may be associated with decreased morbidity for the baby. There was insufficient data for reliable conclusions about the comparative effects on most outcomes for the mother. | Low |
| Vigil-De-Gracia et al. (2013) [121] | Hypertension—Severe preeclampsia between 28 and 33 weeks | RCT | Latin America. Multisite study including 8 tertiary teaching hospitals between 2010 and 2012 | N = 267 To compare planned early birth (n = 133) versus EM (n = 134) | EM was not associated with neonatal benefit and may increase the risk of abruption and small for gestational age. | Low |
| Cluver et al. (2017) [118] | Hypertension—all forms from 34 weeks to term | Cochrane review of RCTs; studies with quasi randomised design or cross-over design were excluded | 5 included RCTs from the Netherlands, India; USA, Saudi Arabia and Egypt (including Hypitat I and II) | N = 1819 To compare planned early birth (n = 915) versus EM (n = 904) | Planned early birth is associated with less composite maternal morbidity and mortality. There is no clear difference in the composite outcome of infant mortality and severe morbidity; however, this is based on limited data (from two trials) assessing all hypertensive disorders as one group. | Low |
| Tajik et al. (2012) [211] | Hypertension and mild preeclampsia between 36 and 41 weeks | Post hoc analysis of RCT (HYPITAT-I) | The Netherlands. | N = 756 (IOL group = 377; EM group = 379) To assess whether cervical ripeness should play a role in the decision for IOL. | The superiority of IOL in preventing high-risk situations varied significantly according to cervical favourability. | Low |
| Walker et al. (2016) [171] | Maternal age | RCT | UK. Multi-centre study including 39 Centers between August 2012 to March 2015 | N = 619 To test if IOL at 39 weeks reduces CS rates for nulliparous women of advanced maternal age (≥ 35) by comparing outcomes for IOL (n = 305) with EM (n = 314). Women who had undergone in vitro fertilization with the use of donor eggs were excluded. | No significant differences in the two groups in terms of CS rates (32% in IOL group vs 33% in EM group; RR 0.99), % of women who had a vaginal birth with the use of forceps or vacuum (38% vs 33%, RR 1.30), the women’s experience of childbirth, or adverse maternal or neonatal outcomes. There were no maternal or infant deaths. | Low |
| Boulvain et al. (2016)‡ [174] | Macrosomia—Suspected | Cochrane review of RCTs between 1995 and 2015; studies with quasi randomised design or cross-over design were excluded | 4 included RCTs that include participants from France, Switzerland Belgium, Israel, USA and UK. | N = 1190 To compare outcomes associated with IOL (n = 590) versus EM (n = 600) for suspected fetal macrosomia between 37 to 40 weeks in non-diabetic women. | IOL had no clear effect on the risk of CS (RR 0.91) or instrumental birth (RR 0.86), but did reduce shoulder dystocia (RR 0.60) and fracture (any) (RR 0.20). There was no strong evidence of any difference between groups for measures of neonatal asphyxia: low infant Apgar scores (<7 at 5 minutes) (RR 1.51) or low arterial cord blood pH (RR 1.01). There was no perinatal mortality, and no differences in the groups in terms of portion of newborns with intraventricular haemorrhage (RR 1.06), nor neonatal intensive care admissions (RR 0.66). | Low |
| Keulen et al. (2018) [34] | Post-term pregnancy | Systematic review | Reviewed evidence from RCTs included in Cochrane review by Middleton, Shepherd [6] | N = 4 RCTs To compare outcomes associated with IOL at 41 weeks versus 42 weeks. | The incidence of potentially gestational age associated perinatal mortality between 41 and 42 weeks was 0/2.444 (0%) for the IOL group versus 4/2.452 (0.16%) in the EM group (number needed to treat was 613). This review concluded that there is not sufficient evidence for IOL at 41 weeks instead of 42 weeks. | Low |
| Keulen et al. (2019) [35] | Post-term pregnancy | RCT | The Netherlands. Multi-site study including 123 primary care midwifery practices and 45 hospitals with data collected between 2012 and 2016. | N = 1801 low risk women with an uncomplicated singleton pregnancy. To compare IOL at 41 weeks (n = 900) versus EM until 42 weeks (n = 901) | IOL was associated with reduced adverse perinatal outcomes (1.7% vs 3.1%, absolute risk difference of 1.4%, 95% CI -2.9 to 0.0, p = 0.22 for non-inferiority). No significant difference was found in composite adverse maternal outcomes or CS rates. | Low |
| Middleton et al. (2018) [6] | Post-term pregnancy | Cochrane review. Cluster RCTs, quasi-RCTs, or cross-over design were excluded. | 30 RCTs (1969–2015) from Norway, China, Thailand, the USA, Austria, Turkey, Canada, UK, India, Tunisia, France, Finland, Spain, Sweden and the Netherlands. | N = 12,479 To assess the effects of a policy of IOL at or beyond term compared with a policy of awaiting spontaneous labour (or until planned birth becomes required) on pregnancy outcomes for infant and mother. Only trials including women at low risk for complications were included. | IOL was associated with fewer perinatal deaths (RR) 0.33) (2 vs 16), lower NICU admissions (RR 0.88), fewer babies had Apgar scores <7 at five minutes (RR 0.70), and fewer CS (RR 0.92). The number needed to treat to in order to prevent one perinatal death was 426. There was no significant difference between groups for perineal trauma (RR 1.09), postpartum haemorrhage (RR 1.09), length of maternal hospital stay, or neonatal trauma (RR 1.18). IOL was associated with an increase in operative vaginal births (RR 1.07), in particular for IOL at < 41 weeks. | Low |
| Bond et al. (2017) [82] | PROM, preterm | Cochrane review of RCTs; quasi RCTs were excluded | USA, the Netherlands, Mexico, Albania, Australia, New Zealand, Argentina, South Africa, Brazil, UK, Norway, Egypt, Uruguay, Poland, and Romania | N = 3617 To compare outcomes associated with planned early birth by CS or IOL with EM for women with PROM of<37 weeks with no maternal or fetal contraindications to EM. | In terms of neonatal outcomes, there were no clear differences in neonatal sepsis (RR 0.93), proven neonatal infection with positive blood culture (RR 1.24), and overall perinatal mortality (RR 1.76), but found that early birth was associated with a higher rate of neonatal death (RR 2.55), respiratory distress syndrome (RR 1.26), need for ventilation (RR 1.27), and NICU admission (RR 1.16). In terms of maternal outcomes, early birth was associated with an increased rate of CS (RR 1.26) and increased rate of endometritis (RR 1.61), and reduced incidence of chorioamnionitis (RR 0.50). | Low |
| Middleton et al. (2017) [81] | PROM, at term | A Cochrane review of randomised and quasi-randomised controlled trials | 23 RCTs (1990–2015) from Pakistan, China, Scotland, Canada, the UK, Australia, Israel, Sweden and Denmark, Brazil, Canada, Denmark, Germany, India, Norway, Serbia, Sweden, the Netherlands, Turkey, USA, and Zimbabwe. | N = 8615 To compare IOL (immediate or within 24 hours) with EM (no planned intervention within 24 hours) for women with PROM of ≥37 weeks with no maternal or fetal contraindications to EM. | Women who had IOL were at a reduced risk of maternal infectious morbidity (chorioamnionitis and/or endometritis) than women who had EM (RR 0.49), and their neonates were less likely to have early-onset neonatal sepsis (RR 0.73). No clear differences were seen for the risk of CS (RR 0.84); serious maternal morbidity or mortality (no events); definite early-onset neonatal sepsis (RR 0.57); or perinatal mortality (RR 0.47). | Low |
| Bond et al. (2015) [185] | Suspected fetal compromise, incl. intrauterine growth restriction and oligohydramnios | A Cochrane review of randomised and quasi randomised controlled trials | 3 RCTs with participants from the Netherlands and Sweden | N = 546 To assess the effects of early birth (n = 269) versus EM (n = 277) of suspected compromised fetus at term (≥ 37 weeks) on neonatal, maternal and long-term outcomes. | There are no major differences in major neonatal and maternal outcomes between the two groups. | Low |
| Stock et al. (2016) [186] | Suspected fetal compromise | A Cochrane review of RCTs; studies with quasi randomised design or cross-over design were eligible but non identified | 1 RCT included conducted between 1993–2001 in 69 hospitals in 13 countries (Belgium, Cyprus, Czech Republic, Germany, Greece, Hungary, Italy, Netherlands, Poland, Portugal, Saudi Arabia, Slovenia, UK). | N = 548 women (588 babies) To assess the effects of immediate (n = 296) versus deferred (n = 291) birth of preterm babies (24–36 weeks) with suspected fetal compromise (and uncertainty about whether to deliver early or not) on neonatal, maternal and long-term outcomes. | For preterm babies with suspected compromise and uncertainty about whether to deliver or not, there appears to be no benefit to immediate birth. | Low |
| Dodd et al. (2014) [156] | Twin pregnancy | Cochrane review of RCTs; studies with cross-over design were excluded | 2 included RCTs. A multi-site study across Australia, New Zealand and Italy, and a single site study from Japan. | N = 271 and 542 infants To compare elective birth by CS or IOL from 37 week (n = 133) with EM (n = 138) for women with an otherwise uncomplicated twin pregnancy. EM = IOL after 38 weeks, spontaneous onset of labour, or CS close to 39 weeks. | No statistically significant differences in CS, perinatal death or serious infant morbidity, or maternal death or serious maternal morbidity. | Low |
†review by Wang et al. (2017) [143] included the same studies.
‡review by Magro-Malosso (2017) [177] included the same studies with similar findings.
EM = expectant management; GDM = Gestational diabetes mellitus; IOL = Induction of labour; CS = Caesarean section; NICU = neonatal intensive care unit