Low molecular weight heparin and pregnancy

(1) Low molecular weight heparins (LMWH) are increasingly used during pregnancy. (2) Clinical data on the use of LMWH during pregnancy are limited. They are drawn mainly from heterogeneous case series, most of which were non comparative and involved prophylaxis rather than therapy. They provide no clear conclusions as to the efficacy and adverse effects of LMWH compared with unfractionated heparin, or the optimal dose regimen during the different phases of pregnancy. (3) No risk of malformations has been reported with LMWH preparations available in France, but data are insufficient to rule out a risk of obstetric, fetal or neonatal problems. (4) Cases of intraspinal haematoma have occurred after epidural anaesthesia. (5) Unfractionated heparin remains the reference treatment during pregnancy.