Quantifying the Risks and Benefits of Continuing Labor Induction: Data for Shared Decision-Making

Effect of Vaginal Washing before Intravaginal Prostaglandin Insertion on Induction of Labor: A Systematic Review and Meta-analysis of Randomized Controlled Trials

OBJECTIVE

Saline vaginal douching prior to intravaginal prostaglandin application might increase the vaginal pH, leading to improvement of prostaglandin bioavailability, by which the outcomes of labor induction can be greatly improved. Thus, we aimed to evaluate the effect of vaginal washing with normal saline before insertion of vaginal prostaglandin for labor induction.

STUDY DESIGN

A systematic search was done in PubMed, Cochrane Library, Scopus, and ISI Web of Science from inception to March 2022. We selected randomized controlled trials (RCTs) that compared vaginal washing using normal saline versus no vaginal washing in the control group before intravaginal prostaglandin insertion during labor induction. We used RevMan software for our meta-analysis. Our main outcomes were the duration of intravaginal prostaglandin application, duration from intravaginal prostaglandin insertion to active phase of labor, duration from intravaginal prostaglandin insertion till total cervical dilatation, labor induction failure rate, incidence of cesarean section (CS), and rates of neonatal intensive care unit (NICU) admission and fetal infection postdelivery.

RESULTS

Five RCTs were retrieved with a total number of 842 patients. Duration of prostaglandin application, duration from prostaglandin insertion to active phase of labor, and time interval from prostaglandin insertion to total cervical dilatation were significantly shorter among vaginal washing group (p < 0.05). Vaginal douching prior to prostaglandin insertion significantly decreased the incidence of failed labor induction (p < 0.001). After the removal of reported heterogeneity, vaginal washing was linked to a significant decline in CS incidence (p = 0.04). In addition, the rates of NICU admission and fetal infection were significantly lower in the vaginal washing group (p < 0.001).

CONCLUSION

Vaginal washing with normal saline before intravaginal prostaglandin insertion is a useful and easily applicable method for labor induction with good outcomes.

KEY POINTS

· Induction of labor is frequently used in the obstetrics field.. · We assessed vaginal washing impact before prostaglandin insertion for labor induction.. · Vaginal washing is an easily applicable method for labor induction with good outcomes..

Validated Calculators Predicting Cesarean Delivery After Induction: Accuracy in an External Population

OBJECTIVE

To evaluate the performance of two previously published calculators in predicting cesarean delivery after induction of labor in an external population.

METHODS

This was a cohort study including all nulliparous pregnant patients with singleton, term, vertex fetuses; intact membranes; and unfavorable cervices who underwent induction of labor between 2015 and 2017 at an academic tertiary care institution. Individual predicted cesarean risk scores were calculated with two previously published calculators. For each calculator, patients were stratified into three risk groups (lower, middle, and upper thirds) of approximately equivalent size. Predicted and observed incidences of cesarean delivery were compared with two-tailed binomial tests of probability in the overall population and in each risk group.

RESULTS

A total of 846 patients met inclusion criteria, and 262 (31.0%) had cesarean deliveries, which was significantly lower than overall predicted rates of 40.0% and 36.2% with the two calculators (both P<.01). Both calculators significantly overestimated risk of cesarean delivery in higher risk tertiles (all P<.05). The areas under the receiver operating characteristic for both calculators were 0.57 or less in the overall population and in each risk group, suggesting poor predictive value. Higher predicted risk tertile in both calculators was not associated with any maternal or neonatal outcomes except wound infection.

CONCLUSION

Both previously published calculators had poor performance in this population, with neither calculator accurately predicting the incidence of cesarean delivery. Patients and health care professionals might be discouraged regarding trial of labor induction by falsely high predicted risk-of-cesarean scores. We caution against widespread implementation of these calculators without further population-specific refinement and adjustment.

Relationship between maternal age and labor induction duration and outcomes in nulliparous women

OBJECTIVE

To determine the relationship between maternal age and labor induction duration among nulliparous women.

METHODS

This retrospective cohort study included nulliparous women with non-anomalous, term, singleton pregnancies undergoing labor induction with intact membranes at a tertiary-care academic hospital from January 2015 to April 2017. Maternal age was stratified as follows: <25 years, 25-29 years, 30-34 years, 35-39 years, and ≥ 40 years. The primary outcome was induction duration, defined as the time the first induction agent was administered to time of birth. Secondary outcomes were cesarean delivery, cesarean indication, hemorrhage, blood transfusion, peripartum infection, composite neonatal morbidity, and induction duration among the subset of women who ultimately underwent cesarean. The data were analyzed using chi-squared and Fisher exact tests. Multivariable regression was used to adjust for maternal race/ethnicity, maternal body mass index, gestational age at start of induction, and induction indication. Hazard ratios were used to calculate induction duration among women who underwent cesarean delivery, stratified by age and adjusted by the same variables.

RESULTS

Among the 955 patients included, the median induction duration was 32.3 h (interquartile range (IQR) 20.4-41.0 h). Women 40 years and older had a slight increase in induction duration (adjusted odds ratio (aOR) 1.03, 95% confidence interval (CI) 1.01-1.05) and a seven-fold increased risk of induction lasting 60 h or longer (adjusted relative risk (aRR) 7.3, CI 1.8-29.9) when compared to those under 25 years of age; otherwise, there was no association between maternal age and labor induction duration. There was no association between age and cesarean delivery, cesarean indication, hemorrhage, transfusion, peripartum infection, or adverse neonatal outcomes. Furthermore, there was no association between maternal age and induction duration even among women who ultimately underwent cesarean.

CONCLUSION

We found no association between maternal age and induction duration for women under 40 years of age. For women 40 years of age and older, these was an increased risk of labor induction lasting 60 h or longer. Despite this, we found no association between maternal age and cesarean delivery or other adverse maternal or fetal outcomes.