%0 Journal Article
%T First trimester anticoagulant exposure and adverse pregnancy outcomes in women with preconception venous thromboembolism: a nationwide cohort study.
%A Søgaard M
%A Skjøth F
%A Nielsen PB
%A Beyer-Westendorf J
%A Larsen TB
%J Am J Med
%V 0
%N 0
%D Nov 2021 16
%M 34798098
%F 5.928
%R 10.1016/j.amjmed.2021.10.023
%X <B>OBJECTIVE: </B>The purpose of this study was to investigate first trimester anticoagulant exposure and risks of adverse pregnancy-related and fetal outcomes.<BR><B>METHODS: </B>Using Danish nationwide registries, we identified all pregnant women with preconception venous thromboembolism, 2000-2017, and linked data on exposure to low-molecular-weight heparin (LMWH), vitamin K antagonist (VKA), or non-VKA oral anticoagulant (NOAC) during pregnancy. We assessed pregnancy-related and fetal outcomes associated with first trimester anticoagulant exposure.<BR><B>RESULTS: </B>Among 4490 pregnancies in women with preconception venous thromboembolism (mean age 31 years, 40% nulliparous), during the first trimester, 63.1% were unexposed, 25.9% were exposed to LMWH, 10.4% VKA, and 0.6% NOAC. Adverse outcomes were lowest in unexposed and LMWH-exposed. Compared with unexposed, VKA was associated with higher risks of preterm (adjusted OR 2.26, 95% CI 1.70 to 2.99) and very preterm birth (adjusted OR 3.78, 95% CI 1.91 to 7.49), shorter mean gestational age was associated with VKA (-7.5 days, 95% CI -9.1 to -5.9 days) or NOAC (-2.3 days, 95% CI -8.4 to 3.8), and lower mean birthweight with VKA (-55 grams, 95% CI -103.1 to -8.5) or NOAC (-190 grams, 95% CI -364.1 to -16.4). Adjusted ORs for small-for-gestational-age infants were 1.07 (95% CI 0.77 to 1.50) with VKA, and 3.29 (95% CI 1.26 to 7.95) with NOAC. Mean 5-minute Apgar score (9.8) and congenital defect prevalence (8.4-10%) varied little across exposure groups.<BR><B>CONCLUSIONS: </B>Fetal risk was lowest in unexposed and LMWH-exposed pregnancies, supporting the recommendation of LMWH during pregnancy. NOAC safety during pregnancy is unclear due to the rarity of NOAC exposure.