Statins during pregnancy: a cohort study using the General Practice Research Database to investigate pregnancy loss

PurposeThe aim of this study was to determine if there are any differences between the types of pregnancy loss experienced by women who have been prescribed a statin just before or early in pregnancy compared with those who have not. MethodsA retrospective cohort study using the General Practice Research Database was carried out. Women aged 10-49years at pregnancy start who received a prescription for a statin in the 3months before and/or during the first trimester of pregnancy were matched to up to 10 pregnancies on age at start date, diabetes and hypertension status before pregnancy. Pregnancies occurring between 1/1/1992 and 31/3/2009 were included. Pregnancy losses were identified and categorised as spontaneous (including miscarriage), induced for medical, other or unknown reasons. Freetext was used to determine the type of loss where this was not clear from the coded medical records. ResultsTwo hundred eighty-one pregnancies potentially exposed to statins were identified and matched to 2643 unexposed pregnancies. About 54.45% of pregnancies potentially exposed to a statin resulted in a delivery compared with 62.81% of those not exposed. 25.27% of all pregnancies potentially exposed to a statin resulted in a spontaneous loss compared with 20.81% in those not exposed. Using a time to event analysis with exposure as a time-dependent covariate gave an adjusted hazards ratio of 1.64 (95%CI 1.10 to 2.46) of spontaneous pregnancy loss in the statin exposed group. ConclusionsThis study is the first to report the differences in types of pregnancy loss following the potential exposure to a statin just before or early in pregnancy. Copyright (c) 2017 John Wiley & Sons, Ltd.