Statin use in pregnancy and risk of congenital malformations: a Norwegian nationwide study

Statins and other lipid-modifying agents (LMAs) have traditionally been contraindicated during pregnancy due to concerns about harmful fetal effects; however, the risks associated with exposure to statins and other LMAs in human pregnancies remain unclear. Therefore, this study aimed to examine the associations between statin and LMA exposure in pregnancy and congenital malformations in offspring, while updating a 2022 meta-analysis with the results from the present study.

National registry data were linked for all pregnant women in Norway in 2005-18. Associations between first-trimester statin prescription fills and congenital malformations were estimated with mixed-effects logistic regression, adjusting for age, parity, pre-pregnancy folate use, smoking in early pregnancy, comorbidity, and co-medication. Meta-analyses were performed with the generic inverse-variance method and random-effects model.

Congenital malformations occurred among 34 755 out of 803 830 (4.3%) statin non-exposed pregnancies, 74 out of 1255 (5.9%) statin-discontinuer pregnancies, and 19 out of 283 (6.7%) statin-exposed pregnancies. Adjusted odds ratios (ORs) for exposed vs non-exposed pregnancies were 1.30 [95% confidence interval (CI) .81-2.09] for any, 1.15 (.61-2.19) for major, and 1.47 (.75-2.89) for minor malformations. In analyses of exposed vs discontinuer pregnancies, there were no associations between statin exposure and any (adjusted OR 1.01, 95% CI .59-1.72), major (1.08, .52-2.25), or minor malformations (.94, .44-2.00). Results were similar across sensitivity analyses. There was also no association between any LMA exposure and heart malformations (adjusted OR 1.22, 95% CI .50-3.01). The updated meta-analysis suggested no increased risk of major (adjusted OR 1.06, 95% CI .86-1.31) or heart malformations (1.24, 95% CI .94-1.64).

In this large, nationwide study and updated meta-analysis, no significant association was observed between first-trimester exposure to statins or other LMAs and congenital malformations. Although limited power may have prevented detection of weak but clinically relevant associations, the findings do not support a strong or independent association between statin exposure in pregnancy and congenital malformations.