Higher Dose of Misoprostol may help Reduce Labor Time in Multiparous Obese Patients: Study

Obesity in pregnancy is associated with prolonged labor and increased perinatal morbidity. Parturients with obesity often experience fewer uterine contractions after receiving misoprostol, a medication commonly used for labor induction. This raises the question of whether the standard dose of misoprostol is equally effective for obese patients compared to non-obese patients. To address this, researchers aimed to determine if a higher dose of misoprostol could reduce the time from induction start to delivery in patients with obesity.

The trial included 180 pregnant women with a body mass index (BMI) of ≥30 kg/m², at ≥36 weeks’ gestation, with singleton pregnancies and cervical dilation of ≤3 cm at admission. Patients were excluded if they had contraindications to vaginal delivery or misoprostol. Participants were randomized to receive either 25 μg or 50 μg of vaginal misoprostol, with stratification based on parity, BMI categories (<40 kg/m² or ≥40 kg/m²), and provider intent to use mechanical dilation. The primary outcome was the time from induction to delivery.

• Out of 180 patients, 88 were assigned to the 25 μg group and 92 to the 50 μg group, with 96.1% of patients receiving their assigned intervention.

• Baseline characteristics were similar between groups.

• The time to delivery did not significantly differ between the two groups, with an average of 21.6 hours in the 25 μg group and 18.6 hours in the 50 μg group (d=.28; 95% CI, −0.02 to 0.57).

• In a subgroup analysis, multiparous patients receiving 50 μg of misoprostol delivered significantly faster (12.0 hours) compared to those receiving 25 μg (15.2 hours) (d=.51; 95% CI, 0.04–0.97).

• The incidence of tachysystole with fetal heart tracing changes was low (2.2%) and similar between groups.

•There were no significant differences in maternal or neonatal adverse effects.

The findings suggest that while the overall time to delivery for obese patients did not significantly differ between 25 μg and 50 μg doses of misoprostol, multiparous patients benefitted from the higher dose. This could imply that dosage adjustments based on parity may optimize labor induction outcomes for obese patients. The study’s results warrant further investigation into the potential of higher doses of misoprostol to reduce labor duration without increasing risks.

In conclusion, a higher dose of misoprostol (50 μg) may be a promising intervention for reducing labor time in multiparous patients with obesity. While the overall time to delivery was not significantly different, the substantial reduction in labor duration for multiparous patients suggests that tailored dosing strategies could enhance labor induction efficiency. These findings highlight the need for further research to confirm the benefits and safety of higher misoprostol doses in this population.

Reference:

Saucedo, A. M., Alvarez, M., Macones, G. A., Cahill, A. G., & Harper, L. M. (2024). Optimal misoprostol dosing among patients with a body mass index greater than 30: a randomized controlled trial. American Journal of Obstetrics and Gynecology, 230(5), 565.e1-565.e16. https://doi.org/10.1016/j.ajog.2024.02.004