Low-molecular-weight heparin in the treatment of recurrent IVF-ET failure and thrombophilia: A prospective randomized placebo-controlled trial

Background Introduction: Recently, thrombophilia (acquired and inherited) has been implicated in recurrent IVF-ET failure. The objective of this study was to determine the effect and safety of thromboprophylaxis using low-molecular-weight heparin (LMWH) in women with recurrent in vitro fertilization (IVF)-embryo transfer (ET) failure and thrombophilia. Methods: Eighty-three women with history of three or more previous IVF failures and who had at least one thrombophilic defect were eligible for this study. Patients were randomly allocated into two groups: Group A (n = 42) received enoxaparin 40 mg day, and group B (n = 41) received placebo (NaCl 0.9%). Both treatments started on the day of ET and continued until delivery or foetal demise was diagnosed. The primary outcomes were the implantation, pregnancy and live birth rates. Results: Patients who received LMWH for thromboprophylaxis had a significant increase in the implantation and pregnancy rates compared with the placebo group (20.9% vs. 6.1% and 31% vs. 9.6%, respectively; p < 0.001 and p < 0.05, respectively). A significant increase in the live birth rate was observed in the heparin-treated group compared with placebo (23.8% vs. 2.8%, respectively; p < 0.05). The abortion rate was significantly higher in the placebo-treated group compared to the heparin-treated group (p < 0.05). The frequency of treatment complications did not differ between the two study groups. Conclusions: LMWH is a safe and effective thromboprophylactic treatment for women with thrombophilia and recurrent IVF-ET failures. The implantation rate, pregnancy and live birth rates are significantly increased with such treatment.