Background.– Some 2.5% of fertile Danish women use sumatriptan, and the drug is also taken during pregnancy. Although sumatriptan reacts selectively in brain vessels, the possibility of reactions with placental blood flow and uterotonic activity cannot be ruled out. The aim of our study was to examine the association between sumatriptan exposure during pregnancy and the risk of preterm delivery and low birth weight.
Methods.– Data from the Pharmaco-Epidemiological Prescription Database of North Jutland county regarding all women who had given birth in the county of North Jutland from 1991 to 1996 were linked to the Danish Medical Birth Registry. Women who were exposed to sumatriptan during pregnancy were identified ( n=34), and using logistic regression models their pregnancy outcome was compared with two groups of pregnant women: (1) healthy women ( n=15 955) and (2) migraine controls ( n=89), defined as migraine patients who did not redeem prescriptions for migraine treatment during pregnancy.
Results.– The risk of preterm delivery was elevated among women exposed to sumatriptan compared with migraine controls (odds ratio [OR] 6.3, 95% confidence interval [CI] 1.2–32.0) and healthy women (OR 3.3, 95% CI 1.3–8.5). The odds ratio for having a newborn with a low birth weight was increased (OR 3.0, 95% CI 1.3–7.0) for all migraine patients who delivered at term ( n=115) compared with the outcome of healthy pregnancies.
Conclusions.– We found that sumatriptan exposure during pregnancy was associated with an increased risk of preterm delivery and low birth weight. These findings may be due to drug exposure, but they may also reflect the impact of disease severity rather than the treatment itself, or confounding, or chance.