PURPOSE: To investigate whether exposure to antazoline-naphazoline eye drops in the first trimester of pregnancy was associated with an increased risk of malformations in humans.

METHODS: All women giving live birth between 1997 and 2011 in Denmark were included in this nationwide cohort study. All women redeeming at least one prescription of antazoline-naphazoline eye drops during the first 84 days of pregnancy were identified. Logistic regression was used to estimate the odds ratios of malformations among exposed offspring compared to non-exposed offspring.

RESULTS: We identified 977 706 births between 1997 and 2011. A total of 3061 women (0.32%) were exposed to antazoline-naphazoline eye drops in the first trimester of pregnancy. The rate of congenital malformations was 3.0% (n = 93) in exposed offspring and 3.5% (n = 33 594) in unexposed offspring. First-trimester exposure to antazoline-naphazoline was not associated with major congenital malformations overall (odds ratio: 0.88, 95% confidence interval: 0.71-1.09) or with any specific major malformation. The number of redeemed prescriptions was unchanged during all trimesters of pregnancy as compared to before and after pregnancy (p < 0.05).

CONCLUSION: Exposure to antazoline-naphazoline eye drops in the first trimester of pregnancy appears not to be associated with increased teratogenic risk.