Induction of labor compared with expectant management for prelabor rupture of the membranes at term. TERMPROM Study Group

The influence of obstetric intervention on trends in twin stillbirths: United States, 1989–99

OBJECTIVE

Although twin stillbirth rates have declined substantially over the past two decades, the contribution of changes in obstetric interventions to reducing twin stillbirths has not been quantified.

METHODS

We carried out a retrospective cohort study of twin live births and stillbirths in the United States between 1989 and 1999 (n=1,102,212). Changes in the rate of stillbirth (> or =22 weeks) before and after adjustment for changes in labor induction, Cesarean delivery and sociodemographic factors were estimated through ecological logistic regression analysis. This analysis was based on aggregating data by each state within the United States.

RESULTS

Between 1989 and 1999, rates of labor induction and Cesarean delivery among twin live births increased by 138% (from 5.8% to 13.8%) and 15% (from 48.3% to 55.6%), respectively. These changes were accompanied by a 43% decline in the stillbirth rate between 1989 and 1999 (from 24.4 to 13.9 per 1000 fetuses at risk). After excluding births weighing < 500 g, rates of labor induction among twins at 22-27 weeks', 28-33 weeks' and > or =34 weeks' gestation increased by 95%, 131% and 127%, respectively, between 1989 and 1999. Cesarean delivery rates also increased by 55%, 29% and 2% in these same gestational age categories. The 48% (relative risk (RR) 0.52, 95% confidence interval (CI) 0.49-0.55) decline in stillbirth rate between 1989-91 and 1997-99 was reduced to a 25% (RR 0.75, 95% CI 0.72-0.79) decline after adjustment for changes in labor induction and Cesarean delivery. The decline in the rate of twin stillbirths was larger at later gestational ages (at > or =32 and > or =34 weeks) where the largest absolute increases in labor induction rates were observed.

CONCLUSIONS

The use of Cesarean delivery and especially labor induction for twin pregnancies has increased substantially in the United States over the last decade and these changes have been associated with a large decline in the rate of stillbirth among twins.

Planned early birth versus expectant management for women with preterm prelabour rupture of membranes prior to 37 weeks' gestation for improving pregnancy outcome

BACKGROUND

Delivery after preterm prelabour rupture of the membranes (PPROM) may be initiated soon after PPROM or, alternatively, be delayed. It is unclear which strategy is most beneficial for mothers and their babies.

OBJECTIVES

To assess the effect of planned early birth compared with expectant management for pregnancies complicated with PPROM prior to 37 weeks' gestation.

SEARCH STRATEGY

We searched the Cochrane Pregnancy and Childbirth Group's Trials Register (May 2009), the Cochrane Central Register of Controlled Trials (The Cochrane Library 2009, Issue 1), MEDLINE (1996 to May 2009), EMBASE (1974 to May 2009), and reference lists of trials and other review articles.

SELECTION CRITERIA

Randomised controlled trials comparing expectant management with early delivery for women with PPROM prior to 37 weeks' gestation. We excluded quasi randomised trials.

DATA COLLECTION AND ANALYSIS

Two review authors independently evaluated trials for inclusion into the review and for methodological quality.

MAIN RESULTS

We included seven trials (690 women) in the review. We identified no difference in the primary outcomes of neonatal sepsis (risk ratio (RR) 1.33, 95% confidence interval (CI) 0.72 to 2.47) or respiratory distress (RR 0.98, 95% CI 0.74 to 1.29). Early delivery increased the incidence of caesarean section (RR 1.51, 95% CI 1.08 to 2.10). There was no difference in the overall perinatal mortality (RR 0.98, 95% CI 0.41 to 2.36), intrauterine deaths (RR 0.26, 95% CI 0.04 to 1.52) or neonatal deaths (RR 1.59, 95% CI 0.61 to 4.16) when comparing early delivery with expectant management. There was no significant difference in measures of neonatal morbidity, including cerebroventricular haemorrhage (RR 1.90 95% CI 0.52 to 6.92), necrotising enterocolitis (RR 0.58, 95% CI 0.08 to 4.08), or duration of neonatal hospitalisation (mean difference (MD) -0.33 days, 95% CI -1.06 to 0.40 days). In assessing maternal outcomes, we found that early delivery increased endometritis (RR 2.32, 95% CI 1.33 to 4.07), but that early delivery had no effect on chorioamnionitis (RR 0.44, 95% CI 0.17 to 1.14). There was a significant reduction of early delivery on the duration of maternal hospital stay (MD -1.13 days, 95% CI -1.75 to -0.51 days).

AUTHORS' CONCLUSIONS

There is insufficient evidence to guide clinical practice on the benefits and harms of immediate delivery compared with expectant management for women with PPROM. To date all of the clinical trials have had methodological weaknesses and have been underpowered to detect meaningful measures of infant and maternal morbidity.

Intravenous oxytocin alone for cervical ripening and induction of labour

BACKGROUND

Oxytocin is the commonest induction agent used worldwide. It has been used alone, in combination with amniotomy or following cervical ripening with other pharmacological or non-pharmacological methods.

OBJECTIVES

To determine the effects of oxytocin alone for third trimester cervical ripening and induction of labour in comparison with other methods of induction of labour or placebo/no treatment.

SEARCH STRATEGY

We searched the Cochrane Pregnancy and Childbirth Group's Trials Register (January 2009) and bibliographies of relevant papers.

SELECTION CRITERIA

Randomised and quasi-randomised trials comparing intravenous oxytocin with placebo or no treatment, or with prostaglandins (vaginal or intracervical) for third trimester cervical ripening or labour induction.

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed eligibility and carried out data extraction.

MAIN RESULTS

Sixty-one trials (12,819 women) are included.When oxytocin inductions were compared with expectant management, fewer women failed to deliver vaginally within 24 hours (8.4% versus 53.8%, risk ratio (RR) 0.16, 95% confidence interval (CI) 0.10 to 0.25). There was a significant increase in the number of women requiring epidural analgesia (RR 1.10, 95% CI 1.04 to 1.17). Fewer women were dissatisfied with oxytocin induction in the one trial reporting this outcome (5.9% versus 13.7%, RR 0.43, 95% CI 0.33 to 0.56).Compared with vaginal prostaglandins, oxytocin increased unsuccessful vaginal delivery within 24 hours in the two trials reporting this outcome (70% versus 21%, RR 3.33, 95% CI 1.61 to 6.89). There was a small increase in epidurals when oxytocin alone was used (RR 1.09, 95% CI 1.01 to 1.17).Most of the studies included women with ruptured membranes, and there was some evidence that vaginal prostaglandin increased infection in mothers (chorioamnionitis RR 0.66, 95% CI 0.47 to 0.92) and babies (use of antibiotics RR 0.68, 95% CI 0.53 to 0.87). These data should be interpreted cautiously as infection was not pre-specified in the original review protocol.When oxytocin was compared with intracervical prostaglandins, there was an increase in unsuccessful vaginal delivery within 24 hours (50.4% versus 34.6%, RR 1.47, 95% CI 1.10 to 1.96) and an increase in caesarean sections (19.1% versus 13.7%, RR 1.37, 95% CI 1.08 to 1.74) in the oxytocin group.

AUTHORS' CONCLUSIONS

Comparison of oxytocin with either intravaginal or intracervical PGE2 reveals that the prostaglandin agents probably increase the chances of achieving vaginal birth within 24 hours. Oxytocin induction may increase the rate of interventions in labour.A suggestion that for women with prelabour rupture of membranes induction with vaginal prostaglandin may increase risk of infection for mother and baby warrants further study.

Vaginal prostaglandin (PGE2 and PGF2a) for induction of labour at term

BACKGROUND

Prostaglandins have been used for induction of labour since the 1960s. Initial work focused on prostaglandin F2a as prostaglandin E2 was considered unsuitable for a number of reasons. With the development of alternative routes of administration, comparisons were made between various formulations of vaginal prostaglandins.

OBJECTIVES

To determine the effects of vaginal prostaglandins E2 and F2a for third trimester cervical ripening or induction of labour in comparison with placebo/no treatment or other vaginal prostaglandins (except misoprostol).

SEARCH STRATEGY

We searched the Cochrane Pregnancy and Childbirth Group's Trials Register (May 2009) and bibliographies of relevant papers.

SELECTION CRITERIA

Clinical trials comparing vaginal prostaglandins used for third trimester cervical ripening or labour induction with placebo/no treatment or other methods listed above it on a predefined list of labour induction methods.

DATA COLLECTION AND ANALYSIS

We assessed studies and extracted data independently.

MAIN RESULTS

Sixty-three (10,441 women) have been included.Vaginal prostaglandin E2 compared with placebo or no treatment reduced the likelihood of vaginal delivery not being achieved within 24 hours (18.1% versus 98.9%, risk ratio (RR) 0.19, 95% confidence interval (CI) 0.14 to 0.25, two trials, 384 women). The risk of the cervix remaining unfavourable or unchanged was reduced (21.6% versus 40.3%, RR 0.46, 95% CI 0.35 to 0.62, five trials, 467 women); and the risk of oxytocin augmentation reduced (35.1% versus 43.8%, RR 0.83, 95% CI 0.73 to 0.94, 12 trials, 1321 women) when PGE2 was compared to placebo. There was no evidence of a difference between caesarean section rates, although the risk of uterine hyperstimulation with fetal heart rate changes was increased (4.4% versus 0.49%, RR 4.14, 95% CI 1.93 to 8.90, 14 trials, 1259 women).PGE2 tablet, gel and pessary appear to be as efficacious as each other and the use of sustained release PGE2 inserts appear to be associated with a reduction in instrumental vaginal delivery rates (9.9 % versus 19.5%, RR 0.51, 95% CI 0.35 to 0.76, NNT 10 (6.7 to 24.0), five trials, 661 women) when compared to vaginal PGE2 gel or tablet.

AUTHORS' CONCLUSIONS

PGE2 increases successful vaginal delivery rates in 24 hours and cervical favourability with no increase in operative delivery rates. Sustained release vaginal PGE2 is superior to vaginal PGE2 gel with respect to some outcomes studied.Further research is needed to assess the best vehicle for delivering vaginal prostaglandins and this should, where possible, include some examination of the cost-analysis.

Induction of labour versus expectant monitoring for gestational hypertension or mild pre-eclampsia after 36 weeks' gestation (HYPITAT): a multicentre, open-label randomised controlled trial

BACKGROUND

Robust evidence to direct management of pregnant women with mild hypertensive disease at term is scarce. We investigated whether induction of labour in women with a singleton pregnancy complicated by gestational hypertension or mild pre-eclampsia reduces severe maternal morbidity.

METHODS

We undertook a multicentre, parallel, open-label randomised controlled trial in six academic and 32 non-academic hospitals in the Netherlands between October, 2005, and March, 2008. We enrolled patients with a singleton pregnancy at 36-41 weeks' gestation, and who had gestational hypertension or mild pre-eclampsia. Participants were randomly allocated in a 1:1 ratio by block randomisation with a web-based application system to receive either induction of labour or expectant monitoring. Masking of intervention allocation was not possible. The primary outcome was a composite measure of poor maternal outcome--maternal mortality, maternal morbidity (eclampsia, HELLP syndrome, pulmonary oedema, thromboembolic disease, and placental abruption), progression to severe hypertension or proteinuria, and major post-partum haemorrhage (>1000 mL blood loss). Analysis was by intention to treat and treatment effect is presented as relative risk. This study is registered, number ISRCTN08132825.

FINDINGS

756 patients were allocated to receive induction of labour (n=377 patients) or expectant monitoring (n=379). 397 patients refused randomisation but authorised use of their medical records. Of women who were randomised, 117 (31%) allocated to induction of labour developed poor maternal outcome compared with 166 (44%) allocated to expectant monitoring (relative risk 0.71, 95% CI 0.59-0.86, p<0.0001). No cases of maternal or neonatal death or eclampsia were recorded.

INTERPRETATION

Induction of labour is associated with improved maternal outcome and should be advised for women with mild hypertensive disease beyond 37 weeks' gestation.

FUNDING

ZonMw.

A systematic review of intentional delivery in women with preterm prelabor rupture of membranes

OBJECTIVE

To evaluate the effect of intentional delivery versus expectant management in women with preterm prelabor rupture of membranes (PPROM).

METHODS

We searched electronic databases and trials registries, contacted experts, and checked reference lists of relevant studies. Studies were included if they were randomized controlled trials comparing intentional delivery versus expectant management after PPROM, the gestational age of participants was between 30 and 36 weeks, and the study reported one of several pre-determined outcomes.

RESULTS

Four studies were included in the meta-analysis. No difference was found between intentional delivery and expectant management in neonatal intensive care unit (NICU) length of stay (LOS) (weighted mean difference (WMD) -0.81 day, 95% confidence interval (CI) -1.66, 0.04), respiratory distress syndrome (risk difference (RD) -0.01, 95% CI -0.07, 0.06), and confirmed neonatal sepsis (RD -0.01, 95% CI -0.05, 0.04). One study found a significantly lower incidence of suspected neonatal sepsis among the intentional delivery group (RD -0.31, 95% CI -0.50, -0.12; number needed to treat (NNT) 3, 95% CI 2, 8). Maternal LOS was significantly shorter for the intentional delivery group (WMD -1.39 day, 95% CI -2.03, -0.75). There was a significant difference in the incidence of clinical chorioamnionitis favoring intentional delivery (RD -0.16, 95% CI -0.23, -0.10; NNT 6, 95% CI 5, 11). There was no significant difference in the incidence of other maternal outcomes, including cesarean section (RD 0.05, 95% CI -0.01, 0.11).

CONCLUSIONS

Intentional delivery may be favorable to expectant management for some maternal outcomes (chorioamnionitis and LOS). There is insufficient evidence to suggest that either strategy is beneficial or harmful for the baby. Large multicenter trials with primary neonatal outcomes are required to assess whether intentional delivery is associated with less neonatal morbidity.

A prospective randomized study comparing misoprostol and oxytocin for premature rupture of membranes at term

OBJECTIVE

The aim of this randomized trial was to compare the efficacy and safety of vaginal misoprostol and oxytocin for cervical ripening and labor induction in patients with premature rupture of membrane (PROM) at term.

METHODS

Ninety-seven women with PROM at term were assigned randomly to receive intravaginal misoprostol or oxytocin. The primary outcome measure was the induction-delivery interval. Secondary outcomes included the number of women who delivered vaginally within 12 hours of the start of the induction in the two groups, the cesarean, hyperstimulation, and failed induction rates, the mode of delivery, and the neonatal outcome.

RESULTS

Forty-eight women were assigned to intravaginal misoprostol and 49 to oxytocin administration. The mean interval from induction to delivery was 10.61 +/- 2.45 hours in the misoprostol group and 11.57 +/- 1.91 hours in the oxytocin group (p = 0.063). The rates of vaginal delivery were 83.3% and 87.7% and cesarean delivery were 16.7% and 8.2% in the misoprostol and oxytocin groups, respectively. Neonatal outcomes were not significantly different. Of the cases, 8.3% in the misoprostol group and 8.2% in the oxytocin group revealed uterine contraction abnormalities.

CONCLUSION

Our study demonstrates that, intravaginally, misoprostol results in a similar interval from induction of labor to delivery when compared to oxytocin.

Ambient air pollutant concentrations during pregnancy and the risk of fetal growth restriction

BACKGROUND

Previous studies of air pollution and birth outcomes have not evaluated whether complicated pregnancies might be susceptible to the adverse effects of air pollution. It was hypothesised that trimester mean pollutant concentrations could be associated with fetal growth restriction, with larger risks among complicated pregnancies.

METHODS

A multiyear linked birth certificate and maternal/newborn hospital discharge dataset of singleton, term births to mothers residing in New Jersey at the time of birth, who were white (non-Hispanic), African-American (non-Hispanic) or Hispanic was used. Very small for gestational age (VSGA) was defined as a fetal growth ratio <0.75, small for gestational age (SGA) as > or =0.75 and <0.85, and 'reference' births as > or =0.85. Using polytomous logistic regression, associations between mean pollutant concentrations during the first, second and third trimesters and the risks of SGA/VSGA were examined, as well as effect modification of these associations by several pregnancy complications.

RESULTS

Significantly increased risk of SGA was associated with first and third trimester PM(2.5) (particulate matter <2.5 microm in aerodynamic diameter), and increased risk of VSGA associated with first, second and third trimester nitrogen dioxide (NO(2)) concentrations. Pregnancies complicated by placental abruption and premature rupture of the membrane had approximately two- to fivefold greater excess risks of SGA/VSGA than pregnancies not complicated by these conditions, although these estimates were not statistically significant.

CONCLUSIONS

These findings suggest that ambient air pollution, perhaps specifically traffic emissions during early and late pregnancy and/or factors associated with residence near a roadway during pregnancy, may affect fetal growth. Further, pregnancy complications may increase susceptibility to these effects in late pregnancy.

Polymorphism of haptoglobin in patients with premature rupture of membrane

PURPOSE

To investigate whether allelic polymorphism of haptoglobin (Hp) is associated with premature rupture of membrane (PROM), the Hp phenotypes of pregnant women with PROM were analyzed.

PATIENTS AND METHODS

The Hp phenotypes of 221 pregnant Korean women (187 control and 34 PROM patients) were determined by benzidine/hydrogen peroxide staining, following native polyacrylamide gel electrophoresis of hemoglobin-mixed sera. The Hp allele frequencies were calculated from the data of Hp phenotypes, and overall association with PROM was evaluated using Pearson Chi-Square test.

RESULTS

The polymorphic distribution of the patients cohort who underwent a normal delivery (control group) was similar to that of healthy Koreans. In contrast, however, patients with PROM showed significantly higher occurrence of the Hp 1-1 phenotype than control group (23.5% vs 8.0%). Hp 2-2 phenotype was lower in PROM cohort (38.2%) than in the control group (48.7%). The Hp(1) allele frequency in PROM group was significantly higher than that in the control group (0.426 vs 0.297, p = 0.034) with odds ratio of 1.762 (95% CI: 1.038 - 2.991).

CONCLUSION

These findings suggest that pregnant Korean women who possess Hp(1) allele (expressed as Hp 1-1 phenotype) have higher incidence of PROM than women with Hp(2) allele (expressed as Hp 2-2 phenotype). This is the first study that evaluated the significance of Hp polymorphism with respect to the development of PROM.

Indications for induction of labour: a best-evidence review

BACKGROUND

Rates of labour induction are increasing.

OBJECTIVES

To review the evidence supporting indications for induction.

SEARCH STRATEGY

We listed indications for labour induction and then reviewed the evidence. We searched MEDLINE and the Cochrane Library between 1980 and April 2008 using several terms and combinations, including induction of labour, premature rupture of membranes, post-term pregnancy, preterm prelabour rupture of membranes (PROM), multiple gestation, suspected macrosomia, diabetes, gestational diabetes mellitus, cardiac disease, fetal anomalies, systemic lupus erythematosis, oligohydramnios, alloimmunization, rhesus disease, intrahepatic cholestasis of pregnancy (IHCP), and intrauterine growth restriction (IUGR). We performed a review of the literature supporting each indication.

SELECTION CRITERIA

We identified 1387 abstracts and reviewed 418 full text articles. We preferentially included high-quality systematic reviews or large randomised trials. Where no such studies existed, we included the best evidence available from smaller randomised trials and observational studies.

MAIN RESULTS

We included 34 full text articles. For each indication, we assigned levels of evidence and grades of recommendation based upon the GRADE system. Recommendations for induction of labour for post-term gestation, PROM at term, and premature rupture of membranes near term with pulmonary maturity are supported by the evidence. Induction for IUGR before term reduces intrauterine fetal death, but increases caesarean deliveries and neonatal deaths. Evidence is insufficient to support induction for women with insulin-requiring diabetes, twin gestation, fetal macrosomia, oligohydramnios, cholestasis of pregnancy, maternal cardiac disease and fetal gastroschisis.

AUTHORS' CONCLUSIONS

Research is needed to determine risks and benefits of induction for many commonly advocated clinical indications.

A randomised controlled trial of amniotomy and immediate oxytocin infusion versus amniotomy and delayed oxytocin infusion for induction of labour at term

BACKGROUND

There is uncertainty as to the optimal time interval between amniotomy and oxytocin administration when inducing labour. The aim of this study was to compare the efficacy of amniotomy and immediate oxytocin infusion with amniotomy and delayed oxytocin infusion for induction of labour at term.

METHOD

A total of 123 women were randomly chosen to receive either amniotomy and immediate oxytocin infusion (referred to as the 'immediate group') or amniotomy and delayed oxytocin infusion (referred to as the 'delayed group'). The main outcome measure was the proportion of women in established labour at 4 h as well as the proportion that delivered within 12 h of amniotomy. Data were analysed using standard statistical methods.

RESULTS

Women in the immediate group were more likely to be in established labour 4 h post-amniotomy [relative risk (RR) 12.8; 95% CI 55.1-111.7], have a shorter amniotomy to delivery interval (P < 0.001) and achieve vaginal delivery within 12 h (RR 1.5; 95% CI 1.2-12.6). There was no difference between the groups with regards to the mode of delivery, incidence of uterine hyperstimulation and abnormal foetal heart rate recording. Compared to the delayed group, women in the immediate group were more likely to be satisfied with the induction process (RR 4.1, 95% CI 1.1-16.1) and the duration of labour (RR 1.8 95% CI 1.0-3.3).

CONCLUSION

In induction of labour at term, amniotomy and immediate oxytocin infusion is associated with the establishment of active labour at 4 h, a shorter amniotomy-delivery interval and greater maternal satisfaction.

Titrated low-dose vaginal and/or oral misoprostol to induce labour for prelabour membrane rupture: a randomised trial

OBJECTIVE

To evaluate the clinical effectiveness and safety of titrated low-dose misoprostol for induction of labour (IOL) in the presence of prelabour rupture of membranes (PROM).

DESIGN

Randomised controlled trial.

SETTING

Maternity units in the UK (9) and Egypt (1).

POPULATION

Women >34 weeks of gestation with PROM, singleton viable fetus and no previous caesarean section.

METHODS

Subjects randomised to IOL with a titrated low-dose misoprostol regimen (oral except if unfavourable cervix, where initial dose vaginal) or a standard induction method, namely vaginal dinoprostone followed by intravenous oxytocin if the cervix was unfavourable or intravenous oxytocin alone if the cervix was favourable.

MAIN OUTCOME MEASURES

Primary outcome measures were caesarean section and failure to achieve vaginal delivery within 24 hours. Analysis was by intention to treat.

RESULTS

The trial did not achieve the planned sample size of 1890 due to failure in obtaining external funding. Seven hundred and fifty-eight women were randomised (375 misoprostol and 383 standard). There were less caesarean section (14 versus 18%, relative risk [RR] 0.79; 95% CI 0.57-1.09) and less women who failed to achieve vaginal delivery within 24 hours in the misoprostol group (24 versus 31%, RR 0.79; 95% CI 0.63-1.00), but the differences were not statistically significant. Subgroup analysis showed that with unfavourable cervix, misoprostol may be more effective than vaginal dinoprostone. There was no difference in hyperstimulation syndrome. There were more maternal adverse effects with misoprostol, but no significant differences in maternal and neonatal complications.

CONCLUSIONS

Titrated low-dose misoprostol may be a reasonable alternative for IOL in the presence of PROM, particularly in women with an unfavourable cervix. Safety and rare serious adverse events could not be evaluated in a trial of this size.

Clinical management of intra-amniotic infection and chorioamnionitis: a review of the literature

Intra-amniotic infection (IAI), or chorioamnionitis, complicates up to 10% of all pregnancies and up to 2% of labors at term. There is a significant risk of complications for the mother and the neonate following IAI, including sepsis and pneumonia. In addition, there is a correlation between IAI and premature rupture of membranes, preterm premature rupture of membranes, preterm labor, and preterm birth. Research in the last decade has also revealed a complex and significant association between IAI and cerebral palsy and other central nervous system damage in both the preterm and term fetus. Timely diagnosis and treatment of IAI can significantly reduce the risk of both maternal and neonatal complications.

Length of rupture of membranes in the setting of premature rupture of membranes at term and infectious maternal morbidity

OBJECTIVE

This study was undertaken to define the time thresholds of increased risk for infectious maternal morbidities with relationship to length of ruptured membranes at term.

STUDY DESIGN

We designed a retrospective cohort study of all women with premature rupture of membranes beyond 37 weeks' gestation at a single institution. Dichotomized time thresholds of length of ruptured membranes before delivery were examined in 2-hour increments using bivariate and multivariable analyses to assess the rates of chorioamnionitis and endomyometritis.

RESULTS

Among the 3841 women meeting inclusion criteria, increased rates of chorioamnionitis and endomyometritis were noted at time thresholds of 12 hours (adjusted odds ratio 2.3 [95% confidence interval, 1.2-4.4]) and 16 hours (adjusted odds ratio 2.5 [95% confidence interval, 1.1-5.6]), respectively.

CONCLUSION

We found that when length of time of ruptured membranes before delivery is examined via dichotomized time thresholds, the risks of chorioamnionitis and endomyometritis are significantly increased at 12 hours and 16 hours, respectively. These time thresholds derived from dichotomized time analyses should be considered during risk-based counseling and labor management in the setting of term premature rupture of membranes.

Induction of labour versus expectant monitoring in women with pregnancy induced hypertension or mild preeclampsia at term: the HYPITAT trial

BACKGROUND

Hypertensive disorders, i.e. pregnancy induced hypertension and preeclampsia, complicate 10 to 15% of all pregnancies at term and are a major cause of maternal and perinatal morbidity and mortality. The only causal treatment is delivery. In case of preterm pregnancies conservative management is advocated if the risks for mother and child remain acceptable. In contrast, there is no consensus on how to manage mild hypertensive disease in pregnancies at term. Induction of labour might prevent maternal and neonatal complications at the expense of increased instrumental vaginal delivery rates and caesarean section rates.

METHODS/DESIGN

Women with a pregnancy complicated by pregnancy induced hypertension or mild preeclampsia at a gestational age between 36+0 and 41+0 weeks will be asked to participate in a multi-centre randomised controlled trial. Women will be randomised to either induction of labour or expectant management for spontaneous delivery. The primary outcome of this study is severe maternal morbidity, which can be complicated by maternal mortality in rare cases. Secondary outcome measures are neonatal mortality and morbidity, caesarean and vaginal instrumental delivery rates, maternal quality of life and costs. Analysis will be by intention to treat. In total, 720 pregnant women have to be randomised to show a reduction in severe maternal complications of hypertensive disease from 12 to 6%.

DISCUSSION

This trial will provide evidence as to whether or not induction of labour in women with pregnancy induced hypertension or mild preeclampsia (nearly) at term is an effective treatment to prevent severe maternal complications.

TRIAL REGISTRATION

The protocol is registered in the clinical trial register number ISRCTN08132825.

Induction of labor with oral misoprostol for premature rupture of membranes at term in women with unfavorable cervix: a randomized, double-blind, placebo-controlled trial

AIM

To evaluate the efficacy and safety of oral misoprostol for labor induction in women with term premature rupture of membranes (PROM) and an unfavorable cervix.

METHODS

We randomized 130 women with PROM of < or =4 h to either oral misoprostol, 50 microg, or a placebo given every 4 h for up to three doses. Intravenous oxytocin was initiated if active labor did not begin within 12 h.

RESULTS

Sixty-four women received oral misoprostol and 66 received placebo. The PROM-to-delivery interval was shorter with misoprostol than with placebo (13.7+/-5.8 vs. 20.3+/-6.8 h, respectively, P<0.05). Misoprostol significantly reduced the need for oxytocin (28.1 vs. 72.7%, P<0.001) and antibiotics (25 vs. 69.7%, P<0.001). No significant differences in cesarean section or hyperstimulation rate were noted.

CONCLUSION

Oral misoprostol given to women with unfavorable cervix soon after term PROM significantly reduces the induction-to-delivery time and the need for oxytocin and antibiotics.

Comparative study of induction of labor in nulliparous women with premature rupture of membranes at term compared to those with intact membranes: Duration of labor and mode of delivery

AIM

To evaluate the effect of premature rupture of membranes (PROM) at term on the duration of labor and mode of delivery in comparison with intact membranes in nulliparous women with an unfavorable cervix whose labor was induced.

METHODS

This retrospective cohort study included all term nulliparous women with an unfavorable cervix requiring labor induction over a 2-year period. Prostaglandin E(2) (dinoprostone) and oxytocin were used for labor induction. Criteria for enrolment included (i) singleton pregnancy; (ii) term nulliparous women; or (iii) Bishop score below 6. Statistics were analyzed with Student's t-test, chi(2)-test, Fisher's exact test, and multiple logistic regression.

RESULTS

Our study subjects were 82 women whose labor was induced for PROM and 219 women with intact membranes whose labor was induced for social or fetal reasons. The mean durations of active phase of labor were not significantly different between women with PROM and those with intact membranes. However, the women with PROM had a significantly longer mean duration of second stage and a higher rate of cesarean delivery for failure to progress than those with intact membranes. Multiple logistic regression demonstrated that only PROM and fetal macrosomia were significantly associated with an increased risk of cesarean delivery for failure to progress after other confounding variables were adjusted.

CONCLUSIONS

Labor induction for PROM at term in nulliparous women with an unfavorable cervix is associated with longer duration of the second stage and a higher risk of cesarean delivery for failure to progress in comparison to those with intact membranes.

Association between lactate in vaginal fluid and time to spontaneous onset of labour for women with suspected prelabour rupture of the membranes

OBJECTIVES

To assess whether lactate determination in vaginal fluid is associated with, and can predict, onset of labour for women with suspected prelabour rupture of the membranes (PROM).

DESIGN

Prospective observational study.

SETTING

Labour ward at Soder Hospital, Stockholm, Sweden.

POPULATION

Women with suspected PROM after 34 weeks of gestation, who later had spontaneous onset of labour (n = 179).

METHODS

All women underwent a speculum examination and a test for determining lactate concentration in vaginal fluid. We used logistic regression to estimate the association between lactate concentration in vaginal fluid and time to onset of labour.

MAIN OUTCOME MEASURES

Time from examination to onset of labour (cervix > or =4 cm), within 24 hours and 48 hours.

RESULTS

The median time interval between examination and spontaneous onset of labour was 8.4 hours for women with 'high' lactate (> or =4.5 mmol/l) and 54 hours for those with 'low' lactate concentrations (<4.5 mmol/l). Among 86 women with high lactate concentrations, 76 (88%) had started labour within 24 hours compared with 20 of 93 (22%) women with low lactate concentrations (OR 27.7, 95% CI 12.2-63.3). After checking for the effect of visible amniotic fluid, the corresponding odds were still substantially increased (OR 13.5, 95% CI 5.3-34.3).

CONCLUSIONS

High lactate concentration (> or =4.5 mmol/l) in vaginal fluid can be used to predict whether a woman with suspected PROM will commence spontaneous onset of labour within 24 or 48 hours.

Natural Prostaglandins for Induction of Labor and Preinduction Cervical Ripening

Prostaglandin (PG) E2 has superseded all other natural prostaglandins for induction of labor and pre-induction cervical ripening. This evolution and its rationale are briefly described. PGE2 has been administered intravenously, orally, vaginally, endocervically, and extra-amniotically for induction of labor. All of these, except the intravenous route, have also been explored for pre-induction cervical ripening. The distinction between formal induction and pre-induction is not always clearly made with many studies pursuing both goals at once. Nevertheless, the effectiveness of PGE2 to achieve ripening and induction is currently beyond doubt. In women with unfavorable induction prospects PGE2 results in lower rates of failed induction and higher rates of delivery within a reasonable interval than amniotomy and/or oxytocin. This also applies to women with prelabor rupture of the membranes, but the relative advantages of PGE2 over traditional methods are less clear for women with a favorable cervix. Vaginal administration of PGE2 has superseded virtually all other routes of PGE2 administration except the endocervical route, which tends to give variable results depending on spillage from the endocervical canal. Doses and formulations of vaginal PGE2 with various gels, tablets, pessaries and slow release inserts have varied widely and continue to do so. There is currently no evidence for the superiority of one PGE2 preparation over another.

Prelabor Rupture of Membranes at Term: Induction Techniques

The clinical management of premature rupture of membranes (PROM) at term has been a matter of considerable controversy. Management options have included expectant management or induction of labor with oxytocin, dinoprostone (PGE2), or misoprostol. Early studies suggested that immediate oxytocin induction of labor might reduce maternal and neonatal infections while increasing risk for cesarean section. The definitive TermPROM study found no difference in neonatal infections between immediate and delayed induction with oxytocin and PGE2. However, neither PGE2 nor delayed induction resulted in fewer cesarean sections than immediate oxytocin. Misoprostol offers several theoretical advantages over oxytocin in the setting of PROM at term. However, randomized trials to date have found no significant advantage for misoprostol administration compared with other agents for women with PROM.

Cochrane reviews in pregnancy: the role of perinatal randomized trials and systematic reviews in establishing evidence

Evidence from randomized trials and systematic reviews provides the highest level of evidence from which to make clinical decisions. There are over 340 Cochrane reviews and protocols in pregnancy and childbirth; these provide the best single source of evidence for care of pregnant women and their babies, and highlight further research priorities. The challenges to health professionals are to ensure that the Cochrane reviews are prepared, kept up to date, and used in clinical care, and where relevant reliable evidence is not available to ensure that high-quality randomized trials are promptly conducted.

Protocol for the immediate delivery versus expectant care of women with preterm prelabour rupture of the membranes close to term (PPROMT) Trial [ISRCTN44485060]

Background

Preterm prelabour rupture of membranes (PPROM) complicates up to 2% of all pregnancies and is the cause of 40% of all preterm births. The optimal management of women with PPROM prior to 37 weeks, is not known. Furthermore, diversity in current clinical practice suggests uncertainty about the appropriate clinical management.

There are two options for managing PPROM, expectant management (a wait and see approach) or early planned birth. Infection is the main risk for women in which management is expectant. This risk need to be balanced against the risk of iatrogenic prematurity if early delivery is planned. The different treatment options may also have different health care costs. Expectant management results in prolonged antenatal hospitalisation while planned early delivery may necessitate intensive care of the neonate for problems associated with prematurity.

Methods/Design

We aim to evaluate the effectiveness of early planned birth compared with expectant management for women with PPROM between 34 weeks and 36⁶ weeks gestation, in a randomised controlled trial. A secondary aim is a cost analysis to establish the economic impact of the two treatment options and establish the treatment preferences of women with PPROM close to term.

The early planned birth group will be delivered within 24 hours according to local management protocols. In the expectant management group birth will occur after spontaneous labour, at term or when the attending clinician feels that birth is indicated according to usual care. Approximately 1812 women with PPROM at 34–36⁶ weeks gestation will be recruited for the trial.

The primary outcome of the study is neonatal sepsis. Secondary infant outcomes include respiratory distress, perinatal mortality, neonatal intensive care unit admission, assisted ventilation and early infant development. Secondary maternal outcomes include chorioamnionitis, postpartum infection treated with antibiotics, antepartum haemorrhage, induction of labour, mode of delivery, maternal satisfaction with care, duration of hospitalisation, and maternal wellbeing at four months postpartum.

Discussion

This trial will provide evidence on the optimal care for women with PPROM close to term (34–37 weeks gestation). Consideration of both the clinical and economic sequelae of the management of PPROM will enable informed decision making and guideline development.

Planned early birth versus expectant management (waiting) for prelabour rupture of membranes at term (37 weeks or more)

BACKGROUND

Prelabour rupture of membranes at term is managed expectantly or by elective birth, but it is not clear if waiting for birth to occur spontaneously is better than intervening.

OBJECTIVES

To assess the effects of planned early birth versus expectant management for women with term prelabour rupture of membranes on fetal, infant and maternal wellbeing.

SEARCH STRATEGY

We searched the Cochrane Pregnancy and Childbirth Group Trials Register (November 2004), the Cochrane Central Register of Controlled Trials (The Cochrane Library, Issue 4, 2004), MEDLINE (1966 to November 2004) and EMBASE (1974 to November 2004).

SELECTION CRITERIA

Randomised or quasi-randomised trials of planned early birth compared with expectant management in women with prelabour rupture of membranes at 37 weeks' gestation or more.

DATA COLLECTION AND ANALYSIS

Two review authors independently applied eligibility criteria, assessed trial quality and extracted data. A random-effects model was used.

MAIN RESULTS

Twelve trials (total of 6814 women) were included. Planned management was generally induction with oxytocin or prostaglandin, with one trial using homoeopathic caulophyllum. Overall, no differences were detected for mode of birth between planned and expectant groups: relative risk (RR) of caesarean section 0.94, 95% confidence interval (CI) 0.82 to 1.08 (12 trials, 6814 women); RR of operative vaginal birth 0.98, 95% 0.84 to 1.16 (7 trials, 5511 women). Significantly fewer women in the planned compared with expectant management groups had chorioamnionitis (RR 0.74, 95% CI 0.56 to 0.97; 9 trials, 6611 women) or endometritis (RR 0.30, 95% CI 0.12 to 0.74; 4 trials, 445 women). No difference was seen for neonatal infection (RR 0.83, 95% CI 0.61 to 1.12; 9 trials, 6406 infants). However, fewer infants under planned management went to neonatal intensive or special care compared with expectant management (RR 0.72, 95% CI 0.57 to 0.92, number needed to treat 20; 5 trials, 5679 infants). In a single trial, significantly more women with planned management viewed their care more positively than those expectantly managed (RR of "nothing liked" 0.45, 95% CI 0.37 to 0.54; 5031 women).

AUTHORS' CONCLUSIONS

Planned management (with methods such as oxytocin or prostaglandin) reduces the risk of some maternal infectious morbidity without increasing caesarean sections and operative vaginal births. Fewer infants went to neonatal intensive care under planned management although no differences were seen in neonatal infection rates. Since planned and expectant management may not be very different, women need to have appropriate information to make informed choices.

Preterm prelabour rupture of the membranes: a survey of current practice

BACKGROUND

Preterm prelabour rupture of the membranes (PPROM) complicates 1-2% of all pregnancies. Risks of remaining in utero need to be balanced against the risks of iatrogenic prematurity if early birth is planned.

AIMS

To assess and further define the current management of women with pregnancies complicated with PPROM in Australia.

METHODS

A mail out questionnaire was sent to all Australian Members and Fellows of the Royal Australian and New Zealand College of Obstetricians and Gynaecologists (RANZCOG).

RESULTS

There were 731 responses from RANZCOG Fellows and Members. Corticosteroids were used routinely in the setting of PPROM by 99% (95% confidence intervals (CI) 98.4-100.0%) of obstetricians. Tocolysis was used commonly by 75% (95% CI 98.4-100.0%). Antibiotics are also used routinely by 63% (95% CI 58.8-67.3%) of Australian obstetricians. For women presenting with PPROM less than 34 weeks' gestation 56% (95% CI 48.1-60.0%) of obstetricians would plan to deliver these women prior to term, while for women presenting with PPROM greater than 34 weeks' gestation 50% (95% CI 46.0-54.8%) would offer delivery to such women prior to term.

CONCLUSIONS

There is significant variation in clinical practice in the management of women who present with PPROM in Australia. There is little consensus regarding the optimal timing of delivery for babies of women with pregnancies complicated with PPROM. The present survey supports the need and feasibility of a randomised controlled trial to assess the appropriate gestation at which to deliver women with PPROM near to term.

Prelabor rupture of membranes at term in low-risk women: induce or wait?

OBJECTIVE

To compare the outcomes of expectant versus induction of labor management of patients presenting with prelabor rupture of membranes (PROM) at term.

STUDY DESIGN

Observational case-control study over a period of 36 months.

SETTING

King Abdulaziz University Hospital, Jeddah, Saudi Arabia.

SUBJECTS

All obstetric patients with no obstetric risk factors, other than PROMs at term, were included in our study. Each patient was matched with a control case, whose labor started with intact membranes.

OUTCOME MEASURES

Length of labor duration, fetal distress, intrapartum pyrexia, rate of cesarean delivery, and Apgar scores at birth.

RESULTS

The length of labor duration was shorter in patients with PROMs at term compared to the control group, but the difference was not statistically significant. Furthermore, cesarean section (CS) rate was 4.5% in the PROMs group versus 5.5% in the control group. Among patients with PROM who received induction of labor management, the rates of intrapartum pyrexia and CS were almost twice than in patients who were managed expectantly. However, the differences were not statistically significant.

CONCLUSION

In the absence of other obstetric and maternal or fetal risk factors, PROMs at term does not seem to constitute additional obstetric risks. Furthermore, expectant management of PROM at term enhances the patient's chance of normal vaginal delivery without an increase in fetal and/or maternal morbidity.

Misoprostol for Labor Induction in Women With Term Premature Rupture of Membranes

OBJECTIVE

To systematically review published data evaluating the comparative use of misoprostol with placebo/expectant management or oxytocin for labor induction in women with term (> or = 36 weeks of gestation) premature rupture of membranes.

DATA SOURCES

PubMed (1966-2005), Ovid (1966-2005), CINAHL, The Cochrane Library, ACP Journal Club, OCLC, abstracts from scientific forums, and bibliographies of published articles were searched using the following keywords: premature rupture of membranes, misoprostol, labor induction, and cervical ripening. Primary authors were contacted directly if the data sought were unavailable or only published in abstract form.

METHODS OF STUDY SELECTION

Only randomized controlled trials evaluating the efficacy and safety of misoprostol in comparison with placebo or expectant management (n = 6) and oxytocin (n = 9) published in either article or abstract form were analyzed and included in the meta-analysis.

TABULATION, INTEGRATION, AND RESULTS

Studies were reviewed independently by all authors. Meta-analysis was performed, and the relative risks (RRs) were calculated and pooled for each study outcome. Misoprostol, compared with placebo, significantly increased vaginal delivery less than 12 hours (RR 2.71, 95% confidence interval [CI] 1.87-3.92, P < .001). Misoprostol was similar to oxytocin with respect to vaginal delivery less than 24 hours (RR 1.07, 95% CI 0.88-1.31, P = .50) and less than 12 hours (RR 0.98, 95% CI 0.71-1.35, P = .90). Misoprostol was not associated with an increased risk of tachysystole, hypertonus, or hyperstimulation syndrome when compared with oxytocin and had similar risks for adverse neonatal and maternal outcomes.

CONCLUSION

Misoprostol is an effective and safe agent for induction of labor in women with term premature rupture of membranes. When compared with oxytocin, the risk of contraction abnormalities and the rate of maternal and neonatal complications were similar among the 2 groups.

Misoprostol versus expectant management in premature rupture of membranes at term

OBJECTIVE

To compare the effectiveness of immediate induction of labour with vaginal misoprostol versus expectant management for 24 hours followed by oxytocin induction in women with premature rupture of membranes at term (term PROM).

DESIGN

An open, randomised, controlled trial.

SETTING

Public university hospital in Campinas City, Brazil.

POPULATION

One hundred and fifty pregnancies, half of them allocated to each group.

METHODS

Statistical analysis used Student's t test, the chi2 test, Fisher's exact test, survival analysis and risk ratio estimates with 95% CI.

MAIN OUTCOME MEASURES

Latency period, recruitment to delivery period, period of hospitalisation, mode of delivery, contractility pattern, fetal wellbeing, labour and delivery complications, neonatal and maternal morbidity.

RESULTS

Both groups had similar general characteristics, but the misoprostol group had a significantly shorter latency period (9.4 vs 15.8 hours), a shorter time interval from recruitment to delivery (18.9 vs 27.5 hours), a shorter period of maternal hospitalisation and a slightly higher proportion of alterations of contractility when compared with the expectant group. Caesarean section rates were 20% in the misoprostol group and 30.7% in the other. There were no differences between them regarding fetal wellbeing, complications during labour and delivery and neonatal or postpartum maternal morbidity. Within 24 hours, 44% of women had delivered in the expectant group against 73.3% in the misoprostol group.

CONCLUSIONS

Immediate labour induction with misoprostol in cases of term PROM shortens the latency period, the total time between recruitment to delivery and the time of maternal hospitalisation, increasing the occurrence of alterations of contractility without any maternal and perinatal outcomes disadvantages.

Abnormalities of the First and Second Stages of Labor

Abnormalities of the first and second stages of labor refer for the most part to abnormal progression of labor. This article discusses the risk factors, diagnoses, management options, and outcomes of the various categories of labor abnormalities, and provides an evidence-based approach where one exists. The article concentrates on the term, healthy woman carrying a singleton, vertex, normally grown fetus with no anomalies.

Role of cytokines in preterm labour and brain injury

Intrauterine infection induces an intra-amniotic inflammatory response involving the activation of a number of cytokines and chemokines which, in turn, may trigger preterm contractions, cervical ripening and rupture of the membranes. Infection and cytokine-mediated inflammation appear to play a prominent role in preterm birth at early gestations (<30 weeks). The role of infection/inflammation in preterm birth in Europe has been incompletely characterised. The rate of preterm birth in Sweden is lower, and the rate of chorioamnionitis, bacterial vaginosis (BV), neonatal sepsis, and urinary tract infections during pregnancy is lower compared with the USA. In a Swedish population of women with preterm labour or preterm premature rupture of the membranes (PPROM) <34 weeks of gestation, microorganisms were detected in the amniotic fluid in 25% of women with PPROM and in 16% of those in preterm labour. Nearly half of these women had intra-amniotic inflammation defined as elevated interleukin-6 (IL-6) and IL-8, and there was a high degree of correlation between cytokine levels and preterm birth or the presence of microbial colonisation. These data do not support the hypothesis that infection-related preterm birth is less frequent in northern Europe than elsewhere. The intra-amniotic inflammatory response has also been associated with white matter injury and cerebral palsy. We find that in experimental models, induction of a systemic inflammatory response using lipopolysaccharide activates toll-like receptors (TLRs), which produce either white matter lesions or increase brain susceptibility to secondary insults. Recently, IL-18 in umbilical blood was shown to correlate with brain injury in preterm infants and IL-18 deficiency in mice decreases CNS vulnerability.

A randomized comparison of oral mifepristone to intravenous oxytocin for labor induction in women with prelabor rupture of membranes beyond 36 weeks' gestation

OBJECTIVE

This study was undertaken to compare the use of oral mifepristone with intravenous oxytocin for labor induction in women with prelabor rupture of membranes (PROM) at 36 weeks' or greater gestational age.

STUDY DESIGN

Sixty-five women with spontaneous PROM were randomly assigned to receive orally administered mifepristone or oxytocin infusion. Two hundred milligrams of mifepristone was administered, and subjects were observed for 18 hours, or intravenous oxytocin was administered.

RESULTS

Thirty-three women received mifepristone and 32 received oxytocin. The average interval from start of induction to delivery was 1194.1 +/- 568.7 minutes for mifepristone-treated subjects and 770.8 +/- 519.9 minutes for oxytocin-treated subjects ( P = .001, log-transformed data). Of 33 mifepristone-treated subjects and 32 oxytocin-treated subjects, 25 (78.1%) and 17 (51.5%), respectively, achieved successful induction (defined as vaginal delivery within 24 hours) (relative risk [RR] 0.66, 95% CI 0.45-0.96, P = .01). There was more fetal distress in the mifepristone-treated group (9 vs 2, RR 4.36, 95% CI 1.02-18.66, P = .02), and a trend toward more cesarean births (7 vs 3, RR 2.26, 95% CI 0.64-7.99, P = .19). Eleven infants of mifepristone-treated women (33.3%) and 3 infants of oxytocin-treated women (9.4%) were admitted to the neonatal intensive care unit (RR 3.56, 95% CI 1.09-11.58, P = .02).

CONCLUSION

Oral mifepristone administration 18 hours before oxytocin infusion did not improve labor stimulation in women with PROM near term, and was associated with more adverse fetal outcomes.

A short history of evidence-based obstetric care

Evidence-based obstetric care is a relatively new concept, which had its origins in the early 1970s when Iain Chalmers and his colleagues in Oxford responded to the statement of Archie Cochrane that much of the evidence underpinning obstetric (and other) practices was flawed. They recognized the importance of the quality of evidence in informing clinical decision making, particularly evidence from randomized trials. This was a shift away from opinion-based obstetrics, which up until then had been the dominant paradigm. Since then, there has been an exponential increase in the number and quality of clinical trials in obstetrics, and with their dissemination through the Cochrane database of systematic reviews, there have been many improvements in obstetric practice, more closely aligning it with sound evidence.

Prelabor rupture of the membranes at term: when to induce labor?

OBJECTIVES

To determine the significant predictors of clinical chorioamionitis and neonatal infection in patients with prelabor rupture of the membranes at term, and to apply this information to determination of optimal timing of labor induction.

STUDY DESIGN

A retrospective case control series of women at > or =37 weeks' with prelabor rupture of the membranes. The study group consisted of women with evidence of maternal or neonatal infection. Controls had no evidence of infection. Three types of management were compared. (1) Immediate induction of labor, (2) expectant management up to 24 h followed by induction of labor if still necessary, or (3) expectant management for over 24 h. Univariate and multivariate analyses were performed by stepwise logistic regression (SPSS software package). The size of the study and the control groups was calculated for a 90% power with two sided P value of 0.05 in order to demonstrate an odds ratio of 2 for expectant management (two groups: early and late) versus immediate induction of labor (132 and 279 women in the study and the control groups, respectively).

RESULTS

The rate of expectant management for over 24 h versus expectant management until 24 h followed by induction of labor when still necessary, was higher among cases than among controls ( OR = 1.84; P < 0.017; 95% CI, 1.127-3.003). Conversely, the rate of immediate induction of labor versus expectant management until 24 h followed by induction of labor when still necessary, was also higher among cases ( OR = 2.66; P < 0.001; 95% CI, 0.222-0.644).

CONCLUSION

In women with prelabor rupture of the membranes at term, the best approach is to induce labor if spontaneous labor has not begun after 24 h.

Vasa Previa: The Impact of Prenatal Diagnosis on Outcomes

OBJECTIVE

To evaluate outcomes and predictors of neonatal survival in pregnancies complicated by vasa previa and to compare outcomes in prenatally diagnosed cases of vasa previa with those not diagnosed prenatally.

METHODS

We performed a multicenter study of 155 pregnancies complicated by vasa previa. Cases were obtained from the Vasa Previa Foundation and 6 large hospitals. Comparisons were made between groups based on prenatal diagnosis status and neonatal survival.

RESULTS

The overall perinatal mortality was 36% (55 of 155). In 61 cases (39%), vasa previa was diagnosed prenatally; 59 of 61 (97%) infants from these pregnancies survived compared with 41 of 94 (44%) in cases not diagnosed prenatally (P <.001). Median 1- and 5-minute Apgar scores in cases diagnosed prenatally were 8 and 9, respectively, compared with 1 and 4 among survivors in cases not diagnosed prenatally (P <.001). More than half (24 of 41) of surviving neonates born to women without prenatal diagnosis required blood transfusions compared with 2 of 59 diagnosed prenatally (P <.001). Multivariable logistic regression analysis showed that the only significant predictors of neonatal survival were prenatal diagnosis (P <.001) and gestational age at delivery (P =.01).

CONCLUSIONS

Good outcomes with vasa previa depend primarily on prenatal diagnosis and cesarean delivery at 35 weeks of gestation or earlier should rupture of membranes, labor, or significant bleeding occur.

Induction of labour with a favourable cervix and/or pre-labour rupture of membranes

Premature rupture of membranes (PROM) occurs in 8% of term deliveries. In this situation labour induction with prostaglandins, compared with expectant management, results in a reduced risk of chorioamnionitis, neonatal antibiotic therapy, neonatal intensive care (NICU) admission, and increased maternal satisfaction. The use of prostaglandin is associated with an increased rate of diarrhoea and use of analgesia/anaesthesia. Compared with oxytocin, prostaglandin induction results in a lower rate of epidural use and internal fetal heart rate monitoring but a greater risk of chorioamnionitis, nausea, vomiting, more vaginal examinations, neonatal antibiotic therapy, NICU admission and neonatal infection. Women should be informed of the risks and benefits of each method of induction.Misoprostol is gaining increasing interest as an alternative induction agent. It appears to be an effective method of labour induction with term PROM. Further research is needed to identify the preferred dosage, route and interval of administration, and to assess uncommon maternal and neonatal outcomes. There has been limited research on the use of prostaglandins, including misoprostol, for induction of labour with a favourable cervix and intact membranes. Compared with intravenous oxytocin (with and without amniotomy), labour induction using vaginal prostaglandins in women with a favourable cervix (with and without PROM) results in a higher rate of vaginal delivery within 24 hours and increased maternal satisfaction. In women with a favourable cervix, artificial rupture of membranes followed by oral misoprostol has similar time to vaginal delivery compared with artificial rupture of membranes followed by oxytocin. Further research with prostaglandins, including misoprostol, is needed to evaluate other maternal and neonatal outcomes in women being induced with a favourable cervix. No form of prostaglandin induction in women with PROM or favourable cervix has proven clearly superior to oxytocin infusion.

The MisoPROM study: A multicenter randomized comparison of oral misoprostol and oxytocin for premature rupture of membranes at term

OBJECTIVE

This study was undertaken to determine whether induction of labor with oral misoprostol will result in fewer cesarean deliveries than intravenous oxytocin in nulliparous women with premature rupture of membranes at term.

STUDY DESIGN

Three hundred five women at 10 centers were randomly assigned to receive oral misoprostol, 100 microg every 6 hours to a maximum of two doses or intravenous oxytocin. The primary outcome measure was cesarean deliveries. Secondary outcomes were time from induction to vaginal delivery and measures of maternal and neonatal safety.

RESULTS

The study was stopped prematurely because of recruitment difficulties. We present the results for the 305 enrolled women. There was no difference in the proportion of women who underwent cesarean delivery (20.1% in the misoprostol group, 19.9% in the oxytocin group). The time interval from induction to vaginal delivery was also similar (11.9 hours for the misoprostol group, and 11.8 hours for the oxytocin group). Maternal and neonatal safety outcomes were similar for the two treatments. More infants born to women in the misoprostol group received intravenous antibiotics in the neonatal period (16.4% vs 6.9%, P=.01), although there were no differences in chorioamnionitis or in proven neonatal infections. Women receiving misoprostol were less likely to have postpartum hemorrhage than those receiving oxytocin (1.9% vs 6.2%, P=.05).

CONCLUSION

Oral misoprostol does not offer any advantage in time from induction to vaginal delivery or risk of cesarean section.