Evaluation of Low-dose and High-dose Intravaginal Misoprostol for Induction of Labour: A Randomised, Double-blinded, Single Centre Study

Abstract

Introduction: Misoprostol is a synthetic prostaglandin E1 analogue widely used for cervical ripening and labour induction. However, misoprostol optimal dose required to induce labour is still controversial. Aim: To determine the efficacy and safety of 25 µg and 50 µg of intravaginal misoprostol for induction of labour at term and to evaluate maternal and neonatal complications. Materials and Methods: The present study was a prospective, randomised, double blind, single centre study carried out during March 2019 to December 2020. All the selected participants were randomised (1:1) to group 1 which received 25 µg of intravaginal misoprostol (n=70) and group 2 received 50 µg of intravaginal misoprostol (n=70). Based on the Bishop’s score, misoprostol was chosen as labour inducing agent. Number of misoprostol doses, mode of delivery, vaginal delivery duration, maternal and neonatal complications was recorded. Statistical significance among study groups were analyzed by using Chi-square test. Results: Postdatism was most frequently reported indication in both the study groups (57.1% and 52.9%). A total of 14 and 4 participants in group 2 and group 1 received only single dose of misoprostol (p<0.01). Participants who received misoprostol 50 µg (n=60, 85.7%) has slightly showed higher vaginal deliveries compared to misoprostol 25 µg (n=57, 81.4%). The mean duration of induction time in group 2 was 10.12 hours and group 1 women showed 13.56 hours (p<0.0001). Maternal and neonatal complications were slightly higher in 50 µg misoprostol group. Maternal complications such as uterine tachysystole (n=4), Postpartum Haemorrhage (PPH) (n=3) and uterine hyperstimulation syndrome (n=2). Neonatal complications with 50 µg misoprostol were Apgar <7 at 1 min (n=4), Apgar <7 at 5 min (n=3), Special Care Baby Unit (SCBU) admissions (n=2) and severe birth asphyxia (n=1). Misoprostol with 25 µg has showed Apgar <7 at 1 min (n=2), Apgar <7 at 5 min (n=2), SCBU admissions (n=1). Conclusion: The efficacy and safety results of 25 µg intravaginal misoprostol were comparable with 50 µg of intravaginal misoprostol for labour induction. The advantages of 50 µg misoprostol were it favours the vaginal deliveries, lesser active induction time and decrease number of misoprostol doses required to induce labour. However, higher dose of misoprostol showed higher frequencies of both maternal and neonatal complications.