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

Fertil Steril. 2004 Dec;82(6):1509-13. doi: 10.1016/j.fertnstert.2004.07.934.


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.

Publication types

  • Clinical Trial
  • Randomized Controlled Trial

MeSH terms

  • Adult
  • Delivery, Obstetric
  • Drug Therapy, Combination
  • Embryo Implantation
  • Embryo Transfer*
  • Female
  • Fertilization in Vitro*
  • Humans
  • Infertility, Female / therapy*
  • Injections, Intramuscular
  • Luteal Phase
  • Phytoestrogens / therapeutic use*
  • Pregnancy
  • Pregnancy Rate*
  • Progesterone / administration & dosage*
  • Progesterone / therapeutic use
  • Prospective Studies
  • Tablets


  • Phytoestrogens
  • Tablets
  • Progesterone