USE OF STATINS IN PREGNANCY

Statins (atorvastatin, fluvastatin, pravastatin, rosuvastatin and simvastatin) are a class of HMG-CoA reductase inhibitors used to lower cholesterol. They are indicated as an adjunct to diet for the treatment of primary hypercholesterolaemia or mixed dyslipidaemia when non-pharmacological treatments (e.g., diet, exercise, weight reduction) are inadequate, or for reduction of cardiovascular morbidity and mortality.

Cholesterol is required for normal development of the placenta and fetus; therefore, theoretical concerns of teratogenic effects exist for any drug that inhibits endogenous cholesterol production. A high proportion of pregnant women taking statins will have pre-existing diabetes, and/or obesity, both of which carry independent risks for fetal malformation and other adverse pregnancy outcomes.

Although the available data are limited for some pregnancy outcomes, they do not suggest that in utero statin exposure increases the risks of overall malformation, stillbirth, preterm delivery, fetal growth impairment or neonatal complications.

Evidence relating to the risk of cardiac malformation is conflicting and possibly confounded; however, a small increased risk cannot be excluded. An absolute risk of approximately 1.5 to 2%, relative to a background risk of approximately 1%, may be suggested by the available data.

Several studies have described small increased risks of miscarriage following maternal statin use in pregnancy; however, these data may be influenced by data confounding and methodological limitations.

Offspring neurodevelopment following gestational statin exposure has not been studied. As neurodevelopmental impairment is a key feature of several genetic cholesterol synthesis disorders, an effect cannot be ruled out and ongoing data collection is required.

Current guidelines on diseases for which statins are frequently prescribed recommend that statins are discontinued three months prior to attempting to conceive, or as soon as pregnancy is confirmed. Where statins are prescribed for conditions associated with high cholesterol, temporary suspension of therapy for the duration of pregnancy is thought unlikely to compromise maternal health. However, there may be some conditions, such as familial hypercholesterolaemia, where continued statin use in pregnancy may be considered. Discussion with UKTIS is recommended in all such cases.

Exposure to statins at any stage of pregnancy would not usually be regarded as medical grounds for termination of pregnancy. However, other risk factors for adverse pregnancy outcome are likely to be present in women exposed to statins, such as obesity and diabetes. Clinicians are reminded of the importance of consideration of such factors when performing case-specific risk assessments.