Objective To select the misoprostol dose to be used in a large multicentre randomised trial comparing misoprostol with oxytocin in the routine management of the third stage of labour.

Design Randomised pilot trial, double-blinded with the use of double placebos.

Setting Two of the nine hospitals that will participate in the main multicentre trial. The hospitals were

Population Women during second stage of labour about to be delivered vaginally.

Methods located in Johannesburg, South Africa and Khon Kaen, Thailand. The trial had three arms: misoprostol 400 μg versus misoprostol 600 μg versus intramuscular oxytocin 10 IU. Each group received an injection and three tablets immediately after the birth of the baby.

Main outcome measures Shivering and pyrexia rates were the main outcome measures. Data on other side effects and characteristics of the third stage of labour were also collected. Side effects were noted as none, mild, moderate or severe.

Results Both shivering and pyrexia (temperature > 38°C) were most common in the 600 μg misoprostol group (28% and 7.5% for shivering and pyrexia, respectively) compared with 400 μg misoprostol (19% and 2%), and the oxytocin group (12.5% and 3%). The increase in shivering in the misoprostol 600 pg group was due primarily to a higher rate of moderate shivering. None of the women had a temperature > 40°C. There were no increases in severe side effects and other adverse events in the misoprostol 600 μg group.

Conclusions When used in the management of the third stage of labour oral misoprostol is associated with an increase in the rate of moderate shivering and pyrexia which seems to be dose-related. Based on the results of this pilot trial, the Steering Committee has decided to use 600 μg misoprostol in the main trial, comparing it with oxytocin, in order to achieve higher effectiveness.