You are here

Sequential use of double-balloon catheter and oral misoprostol versus oral misoprostol alone for induction of labour at term (CRBplus trial): a multicentre, open-label randomised controlled trial.

Kehl S, Ziegler J, Schleussner E, Tuschy B, Berlit S, Kirscht J, Hägele F, Weiss C, Siemer J, Sütterlin M.

BJOG. Oct 20. doi: 10.1111/1471-0528.13116. [Epub ahead of print]

Editor’s comment: Prof. Jim Thornton: Use of balloon catheter prior to misoprostol labour induction is associated with longer induction to birth interval, but perhaps also fewer Caesareans

The CRBplus trial compared misoprostol alone, with pre-treatment with a double balloon catheter followed by misoprostol, for labour induction. The pre-treatment group had longer induction to delivery intervals (median 32.4 hours v. 22.5 hours P = 0.004), but fewer Caesarean deliveries 35 (22%) v. 45 (30%). The latter difference was no statistically significant. The trial was retrospectively registered.



To evaluate the efficacy of inducing labour using a double-balloon catheter and oral misoprostol sequentially, in comparison with oral misoprostol alone.


A multicentre randomised controlled trial.


Five hospitals in Germany.


A total of 326 pregnant women with an unfavourable cervix undergoing labour induction at term.


Women were randomly assigned according to a computer-generated allocation sequence to sequential use of double-balloon catheter and oral misoprostol (study group) or oral misoprostol alone (control group). In the study group, the double-balloon catheter was used the first day before starting oral misoprostol the second day.

Main outcome measures

The primary outcome measure was the induction-to-delivery interval, and a further outcome parameter was delivery within 48 hours.


The median times for induction of labour until delivery were 32.4 hours in the study group and 22.5 hours in the control group (P = 0.004). This difference was not seen when evaluating according to parity (nulliparous, P = 0.19; parous, P = 0.06). The rate of vaginal delivery within 48 hours did not differ between both groups. The number of applications of misoprostol (two versus three, P < 0.001) and the dose of misoprostol used was lower in the study group (100 versus 200 μg, P < 0.001). In the study group, there were more Apgar scores of <7 at 5 minutes (8 versus 1, P = 0.04).


The use of a double-balloon catheter on the first day, before starting oral misoprostol on the second day, did not improve the induction to delivery interval and the rate of delivery within 48 hours, in comparison with oral misoprostol alone.


Subscribe to our E-Alert to stay informed of all new content as it's published on this platform.



Commentaries by Editor Prof. Jim Thornton