Abstract: We included 78 studies (59,216 women) and excluded 34 studies.There was no statistically significant difference in maternal mortality for misoprostol compared with control groups overall (31 studies; 11/19,715 versus 4/20,076 deaths; risk ratio (RR) 2.08, 95% confidence interval (CI) 0.82 to 5.28); or for the trials of misoprostol versus placebo: 10 studies, 6/4626 versus 1/4707 ; RR 2.70; 95% CI 0.72 to 10.11; or for misoprostol versus other uterotonics: 21 studies, 5/15,089 versus 3/15,369 (19/100,000); RR 1.54; 95% CI 0.40 to 5.92. All 11 deaths in the misoprostol arms occurred in studies of misoprostol ≥ 600 µg. There was a statistically significant difference in the composite outcome ‘maternal death or severe morbidity’ for the comparison of misoprostol versus placebo (12 studies; average RR 1.70, 95% CI 1.02 to 2.81; Tau² = 0.00, I² = 0%) but not for the comparison of misoprostol versus other uterotonics (17 studies; average RR 1.50, 95% CI 0.50 to 4.52; Tau² = 1.81, I² = 69%). When we excluded hyperpyrexia from the composite outcome in exploratory analyses, there was no significant difference in either of these comparisons. Pyrexia > 38°C was increased with misoprostol compared with controls (56 studies, 2776/25,647 (10.8%) versus 614/26,800 (2.3%); average RR 3.97, 95% CI 3.13 to 5.04; Tau² = 0.47, I² = 80%). The effect was greater for trials using misoprostol 600 µg or more (27 studies; 2197/17,864 (12.3%) versus 422/18,161 (2.3%); average RR 4.64; 95% CI 3.33 to 6.46; Tau² = 0.51, I² = 86%) than for those using misoprostol 400 µg or less (31 studies; 525/6751 (7.8%) versus 185/7668 (2.4%); average RR 3.07; 95% CI 2.25 to 4.18; Tau² = 0.29, I² = 58%). Misoprostol does not appear to increase or reduce severe morbidity (excluding hyperpyrexia) when used to prevent or treat PPH. Misoprostol did not increase or decrease maternal mortality. However, misoprostol is associated with an increased risk of pyrexia, particularly in dosages of 600 µg or more. Given that misoprostol is used prophylactically in very large numbers of healthy women, the greatest emphasis should be placed on limiting adverse effects. In this context, the findings of this review support the use of the lowest effective dose. As for any new medication being used on a large scale, continued vigilance for adverse effects is essential and there is a need for large randomised trials to further elucidate both the relative effectiveness and the risks of various dosages of misoprostol.

Plain-language summary: This review investigated whether giving misoprostol to women after birth to prevent or treat excessive bleeding reduces maternal deaths and severe complications other than blood loss (which is covered in separate reviews). We included 78 randomised controlled studies involving 59,216 women. The variety of study designs, populations studied, routes of administration and co-interventions, as well as the exceptionally high incidence of hyperpyrexia in Ecuador were limiting factors. Maternal deaths, and the combined outcome, death or severe illness resulting in major surgery, admission to intensive care or vital organ failure (excluding very high fever) were not reduced by misoprostol. The known side effects of misoprostol (fever and very high fever) were worse with dosages of 600 µg or more than with lower dosages. Therefore, the review supports the use of the lowest effective misoprostol dose to prevent or treat maternal bleeding after the birth of the baby, and calls for more research to find out the optimal dosage, with continued surveillance for serious side effects.