Induction of labor in twin pregnancies with oral misoprostol versus vaginal dinoprostone--is it effective and safe?

Methods for the induction of labor: efficacy and safety

This review assessed the efficacy and safety of pharmacologic agents (prostaglandins, oxytocin, mifepristone, hyaluronidase, and nitric oxide donors) and mechanical methods (single- and double-balloon catheters, laminaria, membrane stripping, and amniotomy) and those generally considered under the rubric of complementary medicine (castor oil, nipple stimulation, sexual intercourse, herbal medicine, and acupuncture). A substantial body of published reports, including 2 large network meta-analyses, support the safety and efficacy of misoprostol (PGE1) when used for cervical ripening and labor induction. Misoprostol administered vaginally at doses of 50 μg has the highest probability of achieving vaginal delivery within 24 hours. Regardless of dosing, route, and schedule of administration, when used for cervical ripening and labor induction, prostaglandin E2 seems to have similar efficacy in decreasing cesarean delivery rates. Globally, although oxytocin represents the most widely used pharmacologic agent for labor induction, its effectiveness is highly dependent on parity and cervical status. Oxytocin is more effective than expectant management in inducing labor, and the efficacy of oxytocin is enhanced when combined with amniotomy. However, prostaglandins administered vaginally or intracervically are more effective in inducing labor than oxytocin. A single 200-mg oral tablet of mifepristone seems to represent the lowest effective dose for cervical ripening. The bulk of the literature assessing relaxin suggests this agent has limited benefit when used for this indication. Although intracervical injection of hyaluronidase may cause cervical ripening, the need for intracervical administration has limited the use of this agent. Concerning the vaginal administration of nitric oxide donors, including isosorbide mononitrate, isosorbide, nitroglycerin, and sodium nitroprusside, the higher incidence of side effects with these agents has limited their use. A synthetic hygroscopic cervical dilator has been found to be effective for preinduction cervical ripening. Although a pharmacologic agent may be administered after the use of the synthetic hygroscopic dilator, in an attempt to reduce the interval to vaginal delivery, concomitant use of mechanical and pharmacologic methods is being explored. Combining the use of a single-balloon catheter with dinoprostone, misoprostol, or oxytocin enhances the efficacy of these pharmacologic agents in cervical ripening and labor induction. The efficacy of single- and double-balloon catheters in cervical ripening and labor induction seems similar. To date, the combination of misoprostol with an intracervical catheter seems to be the best approach when balancing delivery times with safety. Although complementary methods are occasionally used by patients, given the lack of data documenting their efficacy and safety, these methods are rarely used in hospital settings.

Effectiveness of dinoprostone gel, misoprostol vaginal insert and dinoprostone vaginal insert for induction of labour in twin pregnancies

OBJECTIVES

To compare the effectiveness and safety of Dinoprostone Gel (DG), Misoprostol Vaginal Insert (MVI) and Dinoprostone Vaginal Insert (DVI) for induction of labour (IOL) in twin pregnancies.

STUDY DESIGN

Retrospective cohort study of twin pregnancies > 34 + 0 weeks gestation that underwent induction of labour (IOL) with DG, MVI or DVI between December 2016 and November 2019 in a Tertiary NHS hospital, North West England, UK. Delivery characteristics, maternal complications and neonatal outcomes were compared between the three groups.

RESULTS

A total of 87 twin pregnancies were included for analysis. 27 women received DG, 34 received MVI and 26 DVI. The MVI cohort had a higher proportion of nulliparous women (55.9%) compared to the DG and DVI cohorts, 29.6% and 38.5% respectively. No other differences amongst demographic characteristics were considered clinically significant. DG demonstrated a significantly quicker time to delivery (minutes) compared to DVI (1021 ± 556 versus 1649 ± 852; P = 0.0026). Significantly fewer women required terbutaline for hyperstimulation/tachysystole in the DG group compared to MVI (0% vs 32%; RR 0.05; 95% CI 0.003-0.88). Both DG and MVI groups required significantly less oxytocin following artificial rupture of membranes compared to DVI (33% vs 65%; RR 0.51; 95% CI 0.28-0.93) and (29% vs 65%; RR 0.45; 95% CI 0.25-0.81). There were no significant differences in mode of delivery, maternal complications and neonatal outcomes.

CONCLUSION

Our data suggests that for women with a twin pregnancy considering a planned labour that induction with DG, MVI and DVI appear to be equally safe and effective IOL methods. These results should be interpreted with caution due to the study being underpowered to detect significant adverse outcomes. In order to determine the optimal method of IOL in twins, direct randomised comparison is needed.

Labour induction in twin pregnancies

Medically-indicated deliveries are common in twin pregnancies given the increased risk of various obstetric complications in twin compared to singleton pregnancies, mainly hypertensive disorders of pregnancy and foetal growth restriction. Due to the unique characteristics of twin pregnancies, the success rates and safety of labour induction may be different than in singleton pregnancies. However, while there are abundant data regarding induction of labour in singleton pregnancies, the efficacy and safety of labour induction in twin pregnancies have been far less studied. In the current manuscript we summarize available data on various aspects of labour induction in twin pregnancies including incidence, success rate, prognostic factors, safety and methods for labour induction in twins. This information may assist healthcare providers in counselling patients with twin pregnancies when labour induction is indicated.

The effect of induction method in twin pregnancies: a secondary analysis for the twin birth study

Background

This secondary analysis for the Twin Birth Study, an international, multicenter trial, aimed to compare the cesarean section rates and safety between methods of induction of labor in twin pregnancies.

Methods

Women with twin pregnancies where the first twin was in a cephalic presentation and who presented for labor induction, were non-randomly assigned to receive prostaglandin or amniotomy and/or oxytocin. Main outcome measures were the rates of unplanned cesarean section and neonatal and maternal mortality or serious morbidity.

Results

153 (41.5%) were induced by prostaglandin (prostaglandin group) and 215 (58.5%) were induced by amniotomy and/or oxytocin alone (no prostaglandin group). Induction using prostaglandin was more common in countries with a low perinatal mortality rate <10/1000 (45.7 versus 32.5%, p = 0.02). Cesarean section rates were similar in the two groups: 62/153 (40.5%) in the prostaglandin group and 87/215 (40.5%) in the no prostaglandin group (odds ratio 1, 95% CI 0.65-1.5). Nulliparity, late maternal age, non-cephalic presentation of twin B and high country’s perinatal mortality rate were found to be independently associated with the induction to end with an unplanned cesarean section. There were no significant differences between groups with respect to maternal or neonatal adverse outcomes.

Conclusions

The need for cervical ripening by prostaglandin had no effect on the incidence of cesarean delivery or an abnormal outcome. There is a significant risk of unplanned cesarean section independent of chosen induction method.

Trial registration

This trial was registered at the International Standard Randomized Controlled Trial Register (identifier ISRCTN74420086; December 9, 2003) and retrospectively registered at the www.clinicaltrials.gov (identifier NCT 00187369; September 12, 2005).

Electronic supplementary material

The online version of this article (doi:10.1186/s12884-016-1201-8) contains supplementary material, which is available to authorized users.