Prenatal exposure to HMG-CoA reductase inhibitors: effects on fetal and neonatal outcomes.

Background: Use of HMG-CoA reductase inhibitors (statins) is becoming increasingly common. However, a recent study based on a series of cases reported to FDA suggests possible teratogenic effects of statins on embryogenesis, such as limb defects and severe central nervous system anomalies.

Methods: In a prospective, observational cohort study with a comparison group to examine a fetal toxicity risk of statins, we followed 64 pregnant women taking statins, and 64 comparison group women without exposure to known teratogens. The statin group women were exposed to atorvastatin (n=46), simvastatin (n=9), pravastatin (n=6), or rosuvastatin (n=3) during the first trimester.

Results: There was no difference in the rate of major malformations between the statin group (1/46 live birth: 2.2%) and the comparison group (1/52 live birth: 1.9%, p=0.93). Similarly, there were no statistical differences between the statin and comparison groups in live births (71.9% vs 81.2%), spontaneous abortions (14: 21.9% vs 11: 17.2%), therapeutic abortions (3: 4.7% vs 0: 0%) and stillbirths (1: 1.5% vs 1: 1.6%). Gestational age at birth (38.4+/-2.8 weeks vs 39.3+/-1.3 weeks: M+/-S.D., p=0.04) and birth weight (3.14+/-0.68kg vs 3.45+/-0.42kg, p=0.01) were lower in the statin group.

Conclusions: The absolute risk of teratogenicity of statins, if any, appears relatively small. A large-scale study is needed to further characterize the teratogenic potential.