Purpose: The efficacy and safety of using mifepristone for the preinduction/induction of labour (IOL) as the only method or in combination with others has been confirmed in observational and randomised trials. However, there are currently no studies comparing the efficacy and safety of using mifepristone for the preinduction of labour on an inpatient and outpatient basis.
Objective: To evaluate whether the outpatient use of mifepristone for cervical ripening before IOL at term is as efficient and safe as in inpatients.
Study design: This open-label, prospective, two-arm, non-inferiority randomised controlled trial (ISRCTN26164110) with a 1:1 allocation ratio was conducted in a single tertiary referral hospital. Overall, 322 pregnant women (gestational age: 39-41 weeks; Bishop score < 6, intact membranes, no contraindications for vaginal delivery, and no contraindications for IOL) were included and randomised:162 to the outpatient group and 160 to the inpatient group for cervical ripening with mifepristone. Analyses were performed based on the intention-to-treat principle.
Results: In 16 % and 17 % of the cases, labour began spontaneously within 24-36 h after taking mifepristone tablets. The additional use of prostaglandin E2 or a balloon for cervical ripening occurred equally often in the compared groups. Oxytocin was used more frequently to induce labour in the inpatient group (P = 0.035). There was no difference in the length of the interval from the onset of cervical ripening to the onset of labour between the groups (38.6 vs. 38.8 h, P = 0.900). The failed induction rate was 1.85 % vs. 0.63 % (P = 0.346).Regional analgesia (P = 0.011) and abnormal foetal heart rate patterns (P = 0.027) were more common in the inpatient group. In the outpatient mifepristone preinduction group, the average time interval from hospitalisation to discharge was 25 h shorter (P < 0.001). No statistically significant differences were observed between the groups in terms of the rates of adverse side effects or perinatal outcomes.
Conclusion: Outpatient cervical ripening with mifepristone reduced the hospital stay duration compared to inpatient ripening, with no difference in efficacy in terms of improvement in the Bishop score, frequency of additional induction method usage, interval from start of preinduction to onset of labour, and labour duration.No differences in the delivery methods, failure rates, or perinatal outcomes were observed. The frequency of adverse effects was low and not related to the setting of the preinduction site. Cervical ripening with mifepristone can be performed on an outpatient basis, because it is as effective and safe as inpatient ripening.
Keywords: Cervical ripening; Induction of labour; Mifepristone; Outpatient; Preinduction.
© 2023 The Authors.