Why should Warfarin be avoided during pregnancy?

Warfarin should be avoided during pregnancy because it is classified as a Category X medication. This classification indicates that studies in animals or humans have demonstrated fetal abnormalities, and the risks of using the medication in pregnant women clearly outweigh any potential benefit. Warfarin can cross the placenta and has been linked to a range of complications such as fetal hemorrhage, teratogenic effects, and other serious outcomes, particularly if used during the first trimester or late in pregnancy when the risk of bleeding increases.

In contrast, Category B medications are considered safe for use in pregnancy, Category C medications have adverse effects on the fetus in animal studies but may be prescribed if the benefits outweigh the risks, and Category D medications have evidence of risk to the fetus but may be used in life-threatening situations where no alternatives are available. Understanding the implications of medication classifications is critical for ensuring maternal and fetal safety during pregnancy.