A total of 82 publications were included in the review. All included studies were blinded randomised controlled trials (RCTs)
For aspirin in high-risk pregnancy, studies did not show a statistically significant effect of aspirin alone on stillbirths (21 RCTs) or perinatal mortality (13 RCTs). For calcium supplementation in low-intake populations, studies showed a statistically non significant effect of calcium supplementation on stillbirths (RR 0.81, 95% CI 0.63 to 1.03; three RCTs) or perinatal mortality (RR 0.86, 95% CI 0.70 to 1.07; four RCTs). For antihypertensive agents in pregnancy with mild to moderate hypertension, studies did not show a statistically significant effect of antihypertensives on stillbirths (18 RCTs) or perinatal mortality (20 RCTs). For magnesium sulphate in pregnancy with pre-eclampsia, studies did not show a statistically significant effect of magnesium sulphate on stillbirths (three RCTs) or perinatal mortality (two RCTs).
For each comparison, results were rated as consistent and heterogeneity was statistically insignificant.