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 BS56 taking oral misoprostol (20 mg first 2 doses followed by 40 mg 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 535 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.

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