What is the optimal duration of oral misoprostol treatment for cervical ripening?

Abstract

Objectives: To evaluate the number of misoprostol tablets needed to obtain a Bishop score (BS) ≥ 6 or a significant cervical change (≥2 points in BS) during cervical ripening.

Methods: Retrospective study of women with term singleton pregnancies and a BS < 6 taking oral misoprostol (20 μg first 2 doses followed by 40 μg every 2 h) for cervical ripening.

Results: We included 400 women, 72% nulliparous, mean age of 31.3 ± 5.9 years and 70% with a baseline BS ≤ 2. During cervical ripening, 61 (15.3%) achieved a BS ≥ 6 and 205 (51.3%) a significant change in BS. The incremental risk to achieve a BS ≥ 6 after 4 tablets was low (+3.25%) with an incremental probability of +12.75% for painful uterine contractions and +0.5% for abnormal fetal tracing (AFT). The incremental probability to achieve a significant change in BS after 7 tablets was low (+2.0%). 24.3% women delivered by cesarean section which likelihood significantly increased with maternal age <35 years, BMI ≥ 30, nulliparity, AFT, and baseline BS ≤ 2.

Conclusions: The marginal benefit of giving more than 7 misoprostol tablets (14 h) during cervical ripening is very low.

• Oral misoprostol
• dosing
• duration
• induction of labor
• cervical ripening

Acknowledgements

We would like to acknowledge R. Sudan for her editing work, Dr. E. Oveisi for his assistance in preparing the manuscript, and Dr. A. Bischofberger for her help in the development of the research protocol.

Declaration of interest

B.M.T. has received travel funding from Besins and ObsEva Laboratories, honoraria from Janssen and ADWYA, and unrestricted grants from Besins and Cepheid Inc. The other authors report no conflict of interest.