Statins in pregnancy

The linked study (doi:10.1136/bmj.h1035) by Bateman and colleagues1 is an important contribution to our knowledge about the teratogenic potential of statins in early pregnancy. It is a well designed epidemiological study of pregnancy and childbirth among a large cohort of US women enrolled in the US Medicaid programme between 2000 and 2007.

The authors analysed 886 996 pregnancies that ended with a liveborn infant, representing approximately 40% of all births in the United States during the study period. They used sophisticated analytical techniques, including high density propensity scoring, to compare otherwise similar women who did or did not use a statin during their first trimester. Propensity scoring helps minimise confounding by adjusting for the many important differences between exposed and unexposed women, such as prevalence of diabetes (which is higher among women taking statins) and use of other drugs. These techniques are rarely used in studies of medicines in pregnant women and are an important strength of the new work.

Bateman and colleagues’ study evaluates the teratogenic potential of statins taken in the first trimester of …