What are the risks of using warfarin during pregnancy?
The most common fetal anomaly developing as a consequence of fetal exposure to warfarin consists of midfacial hypoplasia and stippled epiphyses and typically occurs after in utero exposure to VKAs during the first trimester of pregnancy.421 VKAs have also been associated with CNS abnormalities after exposure during any trimester, but these complications are rare. There is general consensus that in order to minimize the risk of warfarin embryopathy, it is reasonable to avoid warfarin between weeks 6 and 12 of gestation because of the high risk of fetal defects, especially if the dose of warfarin is higher than 5 mg per day.