Delivery outcome after maternal use of drugs for migraine: a register study in Sweden.

Background: The use of drugs for migraine during pregnancy may have adverse effects on delivery outcome, and warnings exist for such drugs regarding use during pregnancy. Most information in the literature concerns triptans.

Objective: The aim of the study was to describe the delivery outcome when a woman had used drugs for migraine during pregnancy.

Study Design: A register study where exposure for drugs was obtained partly by interview conducted by the attending antenatal care midwife and medical records from antenatal care (1995-2008) and partly by linkage to the Prescribed Drug Register (2005-8).

Setting: All deliveries in Sweden (1 211 670 women) recorded in the Medical Birth Register with data from antenatal care.

Patients: Women using triptans or ergots during pregnancy were identified and compared with all women who did not use drugs for migraine.

Main Outcome Measures: Pregnancy complications, pregnancy duration and birthweight, neonatal morbidity and mortality, and congenital malformations.

Results: Use of ergots or triptans during early pregnancy (first trimester) occurred in 3286 women with 3327 infants, while use after the first trimester occurred in 1394 women with 1419 infants. Women using such drugs for migraine were older than other women, were more often of parity 1 (no previous infant) and more often had a high body mass index. Women using drugs for migraine had not previously had more miscarriages than expected. There was an increased risk for pre-eclampsia (odds ratio [OR] 1.44; 95% CI 1.17, 1.76). An increased risk for preterm birth was seen after use of drugs for migraine later in pregnancy (OR 1.50; 95% CI 1.22, 1.84). There was no increased risk for stillbirth or early neonatal death. No certain signs of teratogenicity were found for any of the drug types when compared with women not using such drugs (OR for any malformation 0.95; 95% CI 0.80, 1.12).

Conclusions: Our data suggest that the risk of adverse effects on pregnancy outcome associated with the use of drugs for migraine is low but data for triptans other than sumatriptan are still few.