The time to delivery is similar among patients with obesity taking 50 μg of vaginal misoprostol vs 25 μg of misoprostol, according to a recent study in the American Journal of Obstetrics & Gynecology.1
Takeaways
- Obese patients undergoing induction of labor showed similar time to delivery whether they received 50 μg or 25 μg of vaginal misoprostol, as per a recent study.
- Among multiparous patients, those receiving the higher misoprostol dosage experienced faster delivery times compared to the lower dosage group.
- Patients with a body mass index (BMI) of 40 kg/m2 or higher had a nonsignificant increase in time to delivery compared to those with a BMI of 30 to 39 kg/m2.
- Use of cervical ripening balloon did not significantly affect the time from induction to delivery in obese patients undergoing labor induction.
- Researchers suggest further investigation into the potential benefits of utilizing a higher misoprostol dosage in multiparous obese patients undergoing labor induction.
Approximately 29% of pregnancies are impacted by obesity, defined as a body mass index (BMI) over 30 kg/m2. Adverse pregnancy outcomes associated with obesity include growth abnormalities, diabetes, and pregestational and gestational hypertensive disorders.
Additional risks of obesity include cardiovascular events.2 Hypertensive disorders of pregnancy have been linked to risk factors such as systolic blood pressure and total cholesterol levels, indicating a need for early pregnancy interventions.
Obesity may also lead to a prolonged first stage of labor, increasing risks of cesarean delivery, operative delivery, maternal hemorrhage, and chorioamnionitis.1 Currently, guidelines about cervical ripening regimens do not have specific recommendations for patients with obesity.
Misoprostol is currently used in cervical ripening regimens, and a 25 μg dose is often recommended, with a 50 μg dose employed in certain clinical situations. However, patients with obesity may require an increased dosage.
To evaluate the impact of a 50 μg misoprostol dosage vs a 25 μg dosage on time from induction start to delivery in patients with obesity, investigators conducted a double-blinded, pragmatic randomized controlled trial. Patients aged 18 years and older admitted to the Ascension Seton Medical Center for induction of labor were included in the analysis.
Additional inclusion criteria included near-term singleton gestation, BMI over 30 kg/m2, and cervical dilation of 3 cm or less with an intent to undergo cervical ripening. Exclusion criteria included contraindication to vaginal delivery or misoprostol, fetal demise, major fetal anomaly, and fetal growth restriction under the fifth percentile.
Participants were randomized 1:1 to receive either 50 μg or 25 μg vaginal misoprostol, considered the intervention and control, respectively. Misoprostol was administered every 4 hours for up to 24 hours. The patient’s provider determined when cervical ripening and labor management was needed following the initial misoprostol insertion.
The time to delivery, measured as the time from initiation of induction to delivery, was reported as the primary outcome of the analysis. Secondary outcomes included time to vaginal delivery, time to activate labor, cesarean delivery, delivery within 24 hours, delivery within 12 hours, and indication for cesarean delivery.
There were 179 participants included in the final analysis, 96.1% of whom received the designated intervention. Similar demographic characteristics were reported between patients in the 25 μg and 50 μg groups.
The time from induction to delivery also did not significantly differ between groups, at 21.6 hours in the 25 μg group and 18.6 hours in the 50 μg group. However, when stratified by parity, multiparous patients in the 50 μg experienced faster delivery, at 15.2 hours vs 12 hours, respectively.
Similar results were reported for time to active labor. However, other delivery time points and cesarean delivery rates did not significantly differ between groups. When stratifying patients by a BMI of 40 kg/m2 or higher vs 30 to 39 kg/m2, those with a lower BMI had a nonsignificant time reduction for time to delivery, at 20.18 hours vs 17.15 hours, respectively.
Cervical ripening balloon (CRB) use was determined by provider discretion. The time from induction to delivery did not significantly differ between those who received a CRB vs those who did not receive a CRB.
These results indicated a similar time to delivery between the 25 μg group and the 50 μg group, but reduced time to delivery among multiparous patients. Investigators concluded further research should be conducted about utilizing a higher dose in this population.
References
- Saucedo AM, Alvarez M, Macones GA, et al. Optimal misoprostol dosing among patients with a body mass index greater than 30: a randomized controlled trial. Am J Obstet Gynecol. 2024;230:565.e1-16. doi:10.1016/j.ajog.2024.02.004
- Krewson C. Obesity increases cardiovascular risk from pregnancy complications. Contemporary OB/GYN. October 16, 2023. Accessed May 29, 2024. https://www.contemporaryobgyn.net/view/obesity-increases-cardiovascular-risk-from-pregnancy-complications
