Comparison of labour induction with misoprostol and dinoprostone and characterization of uterine response based on electrohysterogram

Evidence Based Management of Labor

Importance

Induction of labor (IOL) is a common obstetric intervention. Augmentation of labor and active management of the second stage is frequently required in obstetric practice. However, techniques around labor and induction management vary widely. Evidence-based practice regarding induction and labor management can reduce birth complications such as infection and hemorrhage and decrease rates of cesarean delivery.

Objective

To review existing evidence on IOL and labor management strategies with respect to preparing for induction, cervical ripening, induction and augmentation, and second stage of labor techniques.

Evidence acquisition

Review of recent original research, review articles, and guidelines on IOL using PubMed (2000-2022).

Results

Preinduction, pelvic floor training and perineal massage reduce postpartum urinary incontinence and perineal trauma, respectively. Timely membrane sweeping (38 weeks) can promote spontaneous labor and prevent postterm inductions. Outpatient Foley bulb placement in low-risk nulliparous patients with planned IOL reduces time to delivery. Inpatient Foley bulb use beyond 6 to 12 hours shows no benefit. When synthetic prostaglandins are indicated, vaginal misoprostol should be preferred. For nulliparous patients and those with obesity, oxytocin should be titrated using a high-dose protocol. Once cervical dilation is complete, pushing should begin immediately. Warm compresses and perineal massage decrease risk of perineal trauma.

Conclusion and relevance

Several strategies exist to assist in successful IOL and promote vaginal delivery. Evidence-based strategies should be used to improve outcomes and decrease risk of complications and cesarean delivery. Recommendations should be shared across interdisciplinary team members, creating a model that promotes safe patient care.

Assessing uterine electrophysiology prior to elective term induction of labor

OBJECTIVE

The purpose of this study was to determine if uterine electrophysiological signals gathered from 151 non-invasive biomagnetic sensors spread over the abdomen were associated with successful induction of labor (IOL).

STUDY DESIGN

Uterine magnetomyogram (MMG) signals were collected using the SARA (SQUID Array for Reproductive Assessment) device from 33 subjects between 37 and 42 weeks gestational age. The signals were post-processed, uterine contractile related MMG bursts were detected, and parameters in the time and frequency domain were extracted. The modified Bishop score calculated at admission was used to determine the method of IOL. Wilcoxon's rank-sum test was used to compare IOL successes and failures for differences in gestational age (GA), parity, modified Bishop's score, maximum oxytocin, and electrophysiological parameters extracted from MMG.

RESULTS

The average parity was three times (3x) higher (1.53 versus 0.50; p = 0.039), and the average modified Bishop score was 2x higher (3.32 versus 1.63; p = 0.032) amongst IOL successes than failures, while the average GA and maximum oxytocin showed a small difference. For the MMG parameters, successful IOLs had, on average, 3.5x greater mean power during bursts (0.246 versus 0.070; p = 0.034) and approximately 1.2x greater mean number of bursts (2.05 versus 1.68; p = 0.036) compared to the failed IOLs, but non-significant differences were observed in mean peak frequency, mean burst duration, and mean duration between bursts.

CONCLUSION

The study showed that inductions of labor that took less than 24 h to deliver have a higher mean power in the baseline electrophysiological activity of the uterus when recorded prior to planned induction. The results are indicative that baseline electrophysiological activity measured prior to induction is associated with successful induction.

American College of Nurse-Midwives Clinical Bulletin Number 18: Induction of Labor

Induction of labor is an increasingly common component of intrapartum care in the United States. This rise is fueled by a nationwide escalation in both medically indicated and elective inductions at or beyond term, supported by recent research showing some benefits of induction over expectant management. However, induction of labor medicalizes the birth experience and may lead to a complex cascade of interventions. The purpose of this Clinical Bulletin is twofold: (1) to guide clinicians on the use of person-centered decision-making when discussing induction of labor and (2) to review evidence-based practice recommendations for intrapartum midwifery care during labor induction.

Review of Evidence-Based Methods for Successful Labor Induction

Induction of labor is increasingly a common component of the intrapartum care. Knowledge of the current evidence on methods of labor induction is an essential component of shared decision-making to determine which induction method meets an individual's health needs and personal preferences. This article provides a review of the current research evidence on labor induction methods, including cervical ripening techniques, and contraction stimulation techniques. Current evidence about expected duration of labor following induction, use of the Bishop score to guide induction, and guidance on the use of combination methods for labor induction are reviewed.

Is Misoprostol Vaginal Insert Safe for the Induction of Labor in High-Risk Pregnancy Obese Women?

Induction of labor (IOL) is an event that occurs in up to 25% of pregnancies. In Europe, the misoprostol vaginal insert (MVI—Misodel^®) was approved for labor induction in 2013. Studies on the outcomes and safety of IOL in obese pregnant women are scarce; no data are available on MVI IOL in high-risk pregnancy obese women (HRPO—late-term, hypertension, diabetes). As the obesity rates are growing steadily in pregnant women, we aimed to evaluate the failure rate for induction and the safety of a 200 μg MVI in obese (body mass index (BMI) >30 kg/m²) HRPO compared to that for obese non-high-risk pregnancies (non-HRPO). For this purpose, we conducted a cross-sectional study in “Filantropia” Clinical Hospital, Bucharest, Romania, from June 2017—the date of the initiation of the MVI IOL protocol in our clinic—to September 2019. The primary outcomes were the failure rate, measured by cesarean section (CS) ratio, and secondarily, the safety profile of MVI, analyzed by one-way ANOVA. Out of a total of 11,096 registered live births, IOL was performed on 206 obese patients. Of these, 74 obese pregnant women had their labor induced with MVI (HRPO, n = 57, and non-HRPO, n = 17). The average maternal age was 29.9 ± 4.8 years (19–44 years). Across the groups, the rate of CS was 29.8% (n = 17) in the HRPO group compared to 23.5% (n = 4) in the non-HRPO group (p = non significant). In the vaginally birth subgroups, the median time from drug administration to delivery was shorter in the HRPO group compared to the non-HRPO group (16.9 ± 6.0 h 95% confidence interval (CI) 15.0–18.8 vs. 19.4 ± 9.2 h 95% CI 13.8–25.0, p = 0.03). No significant differences were found regarding the maternal outcomes among the studied groups; in terms of perinatal outcomes of safety, 5.4% (n = 4) of the cases of vaginal delivery for HRPO were associated with neonatal intensive care unit (NICU) admissions. The MVI seems to be an efficient labor induction agent in high-risk pregnancy obese women with good maternal outcomes and low perinatologic complications.

Comparison of effectiveness and safety of cervical ripening methods for induction of labour: A population-based study using coarsened exact matching

BACKGROUND

There is no consensus about the ideal cervical ripening method to use for induction of labour.

OBJECTIVE

To compare in current practice the effectiveness and safety of four cervical ripening methods.

METHODS

We performed a matched comparative study using data from the MEDIP prospective population-based cohort conducted during one month in 2015 in all maternity units of seven French perinatal networks (3042 consecutive women with a live fetus and induction of labour). We analysed 1671 women with singleton cephalic fetus, unscarred uterus, and bishop score <7. Dinoprostone vaginal pessary (reference) was compared to dinoprostone vaginal gel, misoprostol vaginal tablet, and balloon catheter. Effectiveness outcomes were the need for more than one induction agent, oxytocin use, failure to achieve vaginal delivery within 24 hours (VD < 24 hours), and caesarean delivery. Safety outcomes were meconium-stained amniotic fluid, uterine hyperstimulation, NICU admission, and post-partum haemorrhage. Coarsened exact matching was used to balance confounders among the groups. Outcomes were compared using multivariable logistic regression models.

RESULTS

Compared to the dinoprostone pessary (N = 1142, 68.3%), dinoprostone gel (N = 335, 20.1%) was associated with less failure to achieve VD < 24 hours (adjusted OR 0.66, 95% CI 0.47, 0.91). Misoprostol (N = 103, 6.2%) was associated with less need of more than one induction agent (aOR 0.56, 95% CI 0.34, 0.92) and less oxytocin use (aOR 0.60, 95% CI 0.37, 0.99). The balloon catheter (N = 91, 5.4%) was associated with more failure to achieve VD < 24 hours (aOR 2.62, 95% CI 1.37, 5.01), more caesarean delivery (aOR 1.84, 95% CI 1.09, 3.08), and less meconium-stained amniotic fluid (aOR 0.12, 95% CI 0.02, 0.70). Uterine hyperstimulation rates seemed lower with the balloon catheter (1.2% vs 4.2% for the pessary).

CONCLUSIONS

In current practice, no cervical ripening method appears clearly superior to the others considering all effectiveness and safety outcomes.

Low-dose vaginal misoprostol vs vaginal dinoprostone insert for induction of labor beyond 41st week: A randomized trial

INTRODUCTION

The aim of this study was to compare the efficacy and safety of a low-dose protocol of vaginal misoprostol and vaginal dinoprostone insert for induction of labor in women with post-term pregnancies.

MATERIAL AND METHODS

We designed a prospective, randomized, open-labeled trial with evaluators blinded to the end-point, including women of at least 41 weeks of gestational age with uncomplicated singleton pregnancies and a Bishop score <6. They were randomized into dinoprostone or misoprostol groups in a 1:1 ratio. Baseline maternal data and perinatal outcomes were recorded for statistical analysis. Successful vaginal delivery within 24 hours was the primary outcome variable. A P value <0.05 was considered statistically significant. This study was registered in ClinicalTrials.gov (number NTC03744364).

RESULTS

We included 198 women for analysis (99 women in each group). Vaginal birth rate within 24 hours did not differ between groups (49.5% vs 42.4%; P = 0.412). When the Bishop score was <4, dinoprostone insert showed a higher probability of vaginal delivery within 12 hours (17.8% vs 4%; P = 0.012). In the dinoprostone group, removal of the insert was more likely to be due to an adverse event (5.1% vs 14.1%; P = 0.051) and an abnormal fetal heart rate pattern during active labor (44.4% vs 58.6%; P = 0.047). Both groups were similar in neonatal outcomes including Apgar score, umbilical cord pH and neonatal intensive care unit admission.

CONCLUSIONS

Low-dose vaginal misoprostol and vaginal dinoprostone insert seem to be equally effective and safe for induction of labor in pregnant women with a gestational age beyond 41 weeks.