Treatment with oxytocin antagonists before embryo transfer may increase implantation rates after IVF

This report aimed to examine the effects of atosiban on pregnancy outcome after IVF–embryo transfer. A prospective, randomized, placebo-controlled clinical study was performed. A total of 180 women undergoing intracytoplasmic sperm injection who had top-quality embryos were randomly allocated into treatment and control groups. All the patients had infertility due to tubal factor, hormonal-anovulatory disorders, male factor or unexplained reasons. The treatment group received intravenous administration of atosiban before embryo transfer with a total administered dose of 37.5 mg. In the control group, the same number of cycles was performed with placebo medication. The clinical pregnancy rate (PR) per cycle and implantation rate (IR) per transfer were 46.7% and 20.4% in the atosiban-treated group, which were significantly higher than in the control group (28.9% and 12.6%, respectively, P = 0.01). The miscarriage rates of groups 1 and 2 were 16.7% and 24.4%, respectively (P = 0.01). These results have indicated that atosiban increases the IR and PR after IVF–embryo transfer. These results suggest that atosiban treatment before embryo transfer is effective in priming of the uterus for implantation. This is the first study to investigate the possible contributions of atosiban for improving the PR after IVF–embryo transfer.