Low molecular weight heparin in obstetric care: a review of the literature.

Low molecular weight heparins (LMWHs) are widely used during pregnancy since several randomized controlled trials have demonstrated their important role in preventing not only thromboembolic disease but also pregnancy complications associated with thrombophilia: recurrent pregnancy loss (RPL), fetal growth restriction (FGR), preeclampsia (PE), abruptio placentae and intrauterine fetal death (IUFD). LMWHs have revealed their effectiveness in reducing the recurrence of negative obstetrics events even in patients without known trombophilias, despite the mechanisms whereby LMWHs operate remain still unclear. However, in order to confirm the suggested benefits, adequately powered and properly controlled trials are needed in this area. Such trials are currently underway and their results will be important to inform evidence-based practice in this area. In our review we report the results of the most relevant trials performed to assess the efficacy of LMWHs in preventing pregnancy complications associated or not with maternal thrombophilia. This review was conducted based on a MEDLINE search for relevant articles between January 2000 and August 2010 and using the following search terms: heparin, low molecular weight heparin, thrombophilia, pregnancy complications, preeclampsia, recurrent pregnancy loss, abruptio placentae, fetal growth restriction.