• Cervical priming;
  • dinoprostone;
  • low-dose misoprostol

Please cite this paper as: Tan T-C, Yan S, Chua T, Biswas A, Chong Y-S. A randomised controlled trial of low-dose misoprostol and dinoprostone vaginal pessaries for cervical priming. BJOG 2010;117:1270–1277.

Objective  We studied the efficacy of 25-μg misoprostol pessaries as either single or double dose compared with a 3-mg dinoprostone pessary for cervical priming.

Design and setting  A randomised controlled trial in Singapore.

Population  One hundred and seventy-one women with term pregnancies and modified Bishop scores (mBS) ≤6 from 2003 to 2004.

Method  Patients were randomised to single misoprostol dose, double misoprostol dose or the current dinoprostone regimen.

Main outcome measures  Primary outcome was number of women who achieved favourable mBS >6 or active labour by day 2. Secondary outcomes were time interval from insertion to delivery, cardiotocographic abnormalities, delivery and neonatal outcome.

Results  More women in the misoprostol double-dose group (96.6%) and dinoprostone group (93%) achieved the primary outcome compared with the single-dose group (77.8%) (P = 0.003 and P = 0.03, respectively). There was no difference in secondary outcomes. More multiparous women achieve primary outcome compared with nulliparous women (odds ratio 0.21, 95% confidence interval 0.06–0.77).

Conclusion  Double-dose misoprostol 25 μg is as effective as dinoprostone 3 mg inserts for cervical priming; both are more efficacious than a single-dose misoprostol pessary. Parity prognosticates the success of induction.