Insertion of a double balloon catheter for induction of labour in pregnant women without previous caesarean section

4.1 A nested study (n=186) within a quasi‑randomised controlled trial (RCT) of 188 pregnant women, comparing a double balloon catheter (DBC) plus extra‑amniotic saline infusion (EASI; n=60) against a single balloon catheter (SBC) plus EASI (n=126), reported that 'ripening success' (defined as an increase in Bishop score of 2 points or more with or without cervical dilation of 3 cm or more) was similar between the DBC and SBC groups (96% versus 93% respectively; p=0.55).

4.2 An RCT of 330 nulliparous pregnant women with unfavourable cervices compared 3 methods (DBC [n=107] versus SBC [n=110] versus prostaglandin gel [dinoprostone, n=113]) for induction of labour at term. The induction‑to‑delivery interval was longer in the DBC group (median 24.5 hours, 95% confidence interval [CI] 23.7 to 30.6) than the SBC group (median 23.2 hours, 95% CI 20.8 to 25.8) or the prostaglandin gel group (23.8 hours, 95% CI 21.7 to 26.8; a single p value of 0.043 was cited). The quasi‑RCT of 188 women at term with singleton pregnancy, comparing DBC (n=100) against SBC plus EASI (n=88) for induction of labour, reported that time from device insertion to delivery was significantly longer in the DBC group compared with the SBC plus EASI group (20.5 hours versus 17.3 hours respectively; p=0.03). The nested study (n=186) in this RCT, comparing DBC plus EASI (n=60) against SBC plus EASI (n=126), reported balloon insertion to delivery interval was significantly shorter in the DBC plus EASI group compared with the SBC plus EASI group (14.2 hours versus 15.5 hours respectively; p=0.04).

4.3 The RCT of 330 nulliparous pregnant women with unfavourable cervices, comparing 3 methods (DBC [n=107] versus SBC [n=110] versus prostaglandin gel [n=113]), reported no difference in caesarean delivery rates between any of the groups (DBC 43% versus SBC 36% versus prostaglandin gel 37%; a single p value of 0.567 was cited). The nested study (n=186) within the quasi‑RCT of 188 women, comparing DBC plus EASI (n=60) against SBC plus EASI (n=126), reported that caesarean section delivery rate was significantly lower in the DBC group than the SBC group (8% versus 20% respectively; p=0.05).

4.4 An RCT of 210 pregnant women with unfavourable cervices, comparing DBC (n=105) against prostaglandin gel (n=103), reported that more women in the DBC group had a vaginal delivery within 24 hours than those in the prostaglandin gel group (69% versus 49% respectively; odds ratio 2.22; 95% CI, 1.26 to 3.91). An RCT of 326 pregnant women with an unfavourable cervix at term, comparing DBC plus oral misoprostol (n=162) against oral misoprostol alone (n=151), reported that the rate of spontaneous vaginal delivery within 48 hours did not differ significantly between the groups (80% [101/162] versus 85% [90/106] respectively; p=0.29).

4.5 The nested study (n=186) within the quasi‑RCT of 188 patients, comparing DBC plus EASI (n=60) against SBC plus EASI (n=126), reported that there was no significant difference in maternal satisfaction (assessed on a scale of 1–10, with higher scores indicating greater satisfaction; 7.7 in the DBC group versus 7.0 in the SBC group, p=0.42). An RCT of 122 women, comparing DBC plus oral misoprostol (n=59) against oral misoprostol alone (n=63), reported a significant positive birth experience (on the German language version of Salmon Item List score) in the DBC plus misoprostol group compared with the misoprostol alone group (87.7 versus 79.3 respectively; p=0.030).

4.6 In the RCT of 326 pregnant women, comparing DBC plus oral misoprostol (n=162) against oral misoprostol alone (n=151), Apgar scores of less than 7 (at 5 minutes) were reported more in the DBC plus oral misoprostol group than in the oral misoprostol alone group (8 versus 1 respectively; p=0.04). In the quasi‑RCT of 188 patients and the nested study (n=186), Apgar scores of less than 7 (at 5 minutes) were similar between the study groups.

4.7 The specialist advisers listed efficacy outcomes as the proportion of women having a vaginal birth or caesarean delivery; the interval from start of induction to delivery; and the change in Bishop's score to enable artificial rupture of membranes (a score of 8 or more indicates that the cervix is ripe).