Phytoestrogens may improve the pregnancy rate in in vitro fertilization-embryo transfer cycles: a prospective, controlled, randomized trial

OBJECTIVE: To compare the effectiveness of i.m. P and i.m. P plus oral phytoestrogens for luteal phase support in patients undergoing IVF-ET cycles. DESIGN: Prospective, controlled, randomized trial. SETTING: University Hospital, Perugia, Italy. PATIENT(S): Two hundred thirteen infertile patients undergoing IVF-ET were included in the study. The inclusion criteria were use of a GnRH agonist for pituitary down-regulation and age <40 years. The total number of cycles performed was 274. INTERVENTION(S): Patients were assigned to receive either i.m. P (50 mg daily) plus placebo or P (50 mg daily) plus phytoestrogen supplementation (1,500 mg daily) for luteal phase support starting from the evening of oocyte retrieval until either a serum pregnancy test result was negative or embryonic heartbeat was sonographically confirmed. MAIN OUTCOME MEASURE(S): The outcomes of IVF-ET were evaluated in both study groups in terms of implantation rate, biochemical pregnancy rate (PR), clinical PR, spontaneous abortion rate, and ongoing pregnancy/delivered rate. RESULT(S): Statistically significant higher values for implantation rate, clinical PR, and ongoing pregnancy/delivered rate were recorded in the patients who received P plus phytoestrogens for luteal phase support in comparison with patients receiving P and placebo. CONCLUSION(S): Although the results of this study encourage the use of phytoestrogens for luteal phase support in patients undergoing IVF-ET program, more studies are necessary to support the hypothesis that phytoestrogens have a beneficial effect in IVF cycles.