Risk of Heparin to a Fetus in Maternal Pulmonary Embolism

Safety Profile of Heparin in Pregnancy

Both low molecular weight heparin (LMWH) and unfractionated heparin (UFH) are considered safe during pregnancy as they do not cross the placenta, preventing fetal exposure and potential teratogenic effects, according to the American College of Chest Physicians 1, 3
LMWH is recommended over UFH for the prevention and treatment of venous thromboembolism (VTE) in pregnant women, with a Grade 1B recommendation from the American College of Chest Physicians 1, 4

LMWH offers a lower risk of heparin-induced thrombocytopenia (HIT) compared to UFH, as reported in Blood advances 2
Extended use of UFH during pregnancy has been associated with a 2.2% risk of osteoporotic fracture, according to Blood advances 2

Vitamin K antagonists, such as warfarin, are contraindicated during pregnancy due to their potential to cause fetal complications, including teratogenicity, pregnancy loss, and fetal bleeding, as stated by the American College of Chest Physicians 1
Oral direct thrombin inhibitors and factor Xa inhibitors should be avoided during pregnancy, with a Grade 1C recommendation from the American College of Chest Physicians 1, 3

In pregnant women with significant renal dysfunction, UFH with activated partial thromboplastin time monitoring is preferred over LMWH, according to Blood advances 2

For pregnant women with acute VTE, anticoagulant therapy should be continued for at least 6 weeks postpartum, with a minimum total duration of 3 months, as recommended by the American College of Chest Physicians and the European Heart Journal 1, 5
Treatment can be safely continued during breastfeeding, as both LMWH and UFH are recommended for lactating women who wish to breastfeed, according to the American College of Chest Physicians 1, 4