Safety of low-molecular-weight heparin in pregnancy: A systematic review

Unfractionated heparin (UFH) remains the anticoagulant of choice during pre gnancy. Low-molecular-weight heparins (LMWH) are an attractive alternative to UFH due to their logistic advantages and their association with a lower incidence of osteoporosis and HIT. We reviewed all published clinical repor ts concerning the use of LMWH during pregnancy. In addition, participants o f an international interest group contributed a cohort of pregnant women tr eated with LMWH. Pregnancies were divided into two groups; those with and t hose without maternal comorbid conditions. The number of adverse fetal outc omes and the occurrence of maternal complications were evaluated in the two groups. In the group of women with comorbid conditions (n = 290), 13.4% of the pregnancies were associated with an adverse fetal outcome. In contrast , in the group of women without comorbid conditions (n = 196), 3.1% were as sociated with an adverse outcome, which is comparable to that seen in the n ormal population. We conclude that LMWH appear to be a safe alternative to unfractionated heparin as an anticoagulant luring pregnancy.