Low molecular weight heparins and their use in obstetrics and gynecology.

A low molecular weight (LMW) heparin, has recently been approved for clinical use in the prevention of deep vein thrombosis in patients undergoing hip surgery. This product is enoxaprin (Lovenox, Rhone-Poulenc Rorer Pharmaceuticals, Paris, France). The purpose of this review is to examine the possible use of LMW heparin in obstetrics and gynecology. LMW heparins are fragments of standard heparin and show a similar anticoagulant effect. The risk of bleeding complications and thrombocytopenia is reduced with the use of these agents. This may be due to their lesser effects on factor II and platelet factor 4. The enhanced bioavailability of these drugs, in conjunction with their prolonged half-life, makes subcutaneous therapy, in one to two daily doses, possible. A review of the published experience of the utilization of LMW heparins in Obstetrics and Gynecology revealed that 1) LMW heparins are effective and safe in the prevention of thromboembolic complications in gynecologic surgery. 2) LMW heparins do not cross the placenta in any trimester. 3) There is no evidence of any mutagenic and teratogenic effect of these drugs. 4) The clinical experience, although limited, suggests their safety and effectiveness in thromboprophylaxis and treatment during pregnancy.