Preinduction cervical ripening in an outpatient setting: a prospective pilot study of a synthetic osmotic dilator compared with a double-balloon catheter

Objectives To compare the effectiveness, safety and patient satisfaction of a double balloon catheter (DB) with a synthetic osmotic cervical dilator (OD) for pre-induction cervical ripening in an outpatient setting. Methods This is a prospective, dual-center pilot study including 94 patients with an unripe cervix (Bishop Score <6) near term; 50 patients received the DB and 44 patients the OD. The primary outcomes were the difference in Bishop Score (BS) and cervical shortening. Pain perception at insertion and during the cervical ripening period was evaluated by a visual analogue scale and patient satisfaction by a predefined questionnaire. Results The use of DB was associated with a significantly higher increase in BS (median 3) compared to OD (median 2; p=0.002) and resulted in significantly greater cervical shortening (median -14 mm vs. -9 mm; p=0.003). There were no serious adverse events at placement of devices or during the cervical ripening. There were no significant differences in perinatal outcomes. Pain perception during cervical ripening was significantly higher (p<0.001), and patient satisfaction regarding sleep, relaxing time and performing desired daily activities were significantly lower in patients with DB compared to patients with OD (p<0.001). Conclusions DB was superior to OD regarding cervical ripening based on BS and on sonographic measurement of the cervical length. Patients with OD experienced less pain during cervical ripening and were more satisfied with the method compared to patients with DB.