Effect of Maternal Age and Body Mass Index on Induction of Labor Using Oral Misoprostol in Late-Term Pregnancies: A Retrospective Cross-Sectional Study

Abstract

Objectives: To evaluate the effect of maternal age and body mass index (BMI) on oral misoprostol induction of labor for late-term pregnancies. Design: Retrospective cross-sectional study (ClinicalTrial iD: NCT06184139), including only late-term pregnancies in healthy nulliparous women and single cephalic fetus with normal birthweight. Specify the type of study (randomized, prospective cohort, case-control, other) and include the number of study subjects (cases/controls), treatment type and duration, sampling procedures if applicable. Participants/materials, setting, methods: One-hundred-and-four pregnant women underwent induction of labor with oral misoprostol for late-term pregnancy on the 290th day of gestation. Study population was divided in two groups based on age (<35 and ≥35 years) and obesity (BMI <30 and ≥30). Statistical analysis was performed using SPSS V.21.0 (IBM Corporation, Armonk, NY). The inclusion of 51 women from each of the two arms achieved 80% power with an alpha error of 0.05. Continuous variables were expressed as the mean and standard deviation (SD). Categorical variables are expressed as frequencies and percentages. Results No statistically significant differences were recorded between younger and older women. Obese women reported a longer time between the last dose of misoprostol and cervical dilation of 6 cm (p=0.01), a longer time between the last dose of misoprostol and delivery (p=0.04), and a higher rate of grade II vaginal lacerations (p=0.02). Limitations While this study contributes novel insights into cervical ripening and labor induction using oral misoprostol for late-term pregnancies, its scope is limited by the retrospective study design, inherently carrying biases compared to prospective approaches, and the limited sample size within the study cohort. Conclusions Maternal BMI is a factor negatively influencing the efficacy of oral misoprostol for induction of labor in late-term pregnancy.