The effect of misoprostol on postpartum contractions: a randomised comparison of three sublingual doses

To compare the postpartum uterine activity and side effects of various doses of sublingual misoprostol and intramuscular oxytocin.

Single centre, randomised trial.

Zliten Teaching Hospital in Libya.

Forty-nine women who did not receive oxytocics in labour and who delivered vaginally.

Thirty-five women were randomised to receive 200, 400 or 600 mcg of sublingual misoprostol PPH prophylaxis immediately following delivery. These were compared with 14 consecutive women given 10 IU of intramuscular oxytocin. Immediately after placental delivery, a Koala intra uterine pressure catheter was inserted transcervically into the uterine cavity.

Main outcomes measures are the uterine pressure (in Montevideo units) measured over 120 minutes. Other outcomes included temperature and measured blood loss.

Women's age, parity, gestational age and neonatal birth weight were not significantly different between the four groups. There was no difference in intrauterine pressure between the three misoprostol doses. However, the uterine pressure was significantly lower than oxytocin with all three doses for the first 10 minutes (P < 0.008) and significantly higher than oxytocin from 50 to 120 minutes (P < 0.008). A dose-related rise in the body temperature and chills was observed in the misoprostol groups, with 8.3%, 8.3% and 45% of women experiencing a fever >39 °C with the 200, 400, and 600 mcg doses respectively.

Intramuscular oxytocin has the highest immediate post partum uterine activity. Lower doses of misoprostol may be as effective as high doses and with fewer side effects. Clinical outcomes with low-dose misoprostol should be further explored (ISRCTN97277056).