Metamizol (dipyrone, optalgin) in pregnancy, is it safe? A prospective comparative study

Aim: To assess the teratogenic effect of metamizol when used during the first trimester of pregnancy. Methods: One hundred and eight women who used metamizol during the first trimester of pregnancy were recruited from 4 teratogen information centers in Israel (3) and in Italy (1). The study group was paired for age, smoking habits and alcohol consumption with a comparative group exposed to acetaminophen. Results: Maternal demographics and history, birth weight, gestational age at delivery, rate of live births, spontaneous abortions and fetal distress were comparable in both groups. The rate of major malformations in the metamizol group (3%) did not differ significantly from the rate in the comparative group (2%) (P = 0.57, relative risk = 1.55, 95% confidence interval 0.26-9.05). Conclusions: Our data may suggest that exposure to metamizol during the first trimester of pregnancy is probably not associated with a significantly increased risk for malformations or spontaneous abortions.