Summary
The use of anticoagulants during pregnancy is problematic because of the potential
adverse effects to the mother and the fetus. Heparin does not cross the placenta,
and thus, it was surprising that a recent report concluded that heparin therapy during
pregnancy was as risky as oral anticoagulant therapy. Therefore, we performed a literature
review of fetal/infant outcomes following anticoagulant therapy during pregnancy.
We examined 186 reports which described fetal/infant outcomes in 1,325 pregnancies
associated with anticoagulant therapy. The rates of adverse fetal/infant outcomes
including death, prematurity and congenital malformations following treatment with
heparin, oral anticoagulants, or both were calculated. The previously described high
rate of adverse feta/infant outcomes with heparin- treated patients, could be accounted
for by the frequent use of heparin in pregnancies with comorbid conditions independently
associated with adverse outcomes and by reports of uncomplicated prematurity. After
excluding such pregnancies, outcomes in heparin-treated patients are similar to the
normal population.
Keywords
Pregnancy - Heparin - Oral anticoagulants - Thromboembolism
