Increasing uterine receptivity by decreasing estradiol levels during the preimplantation period in high responders with the use of a follicle-stimulating hormone step-down regimen

Abstract

Objective: To analyze the effect on uterine receptivity of a decrease in E2 levels during the preimplantation period with the use of a step-down regimen in high responders undergoing IVF.

Design: Prospective controlled clinical study.

Setting: The Instituto Valenciano de Infertilidad.

Patient(s): High responders in whom at least one previous IVF attempt failed in which 3-4 good-quality embryos were transferred and E2 levels were >3,000 pg/mL on the day of hCG administration.

Intervention(s): Gonadotropins were administered according to two different protocols. Blood samples were collected and IVF was performed.

Main outcome measure(s): Serum E2 levels and reproductive outcome of IVF.

Result(s): Estradiol levels on the day of hCG administration and throughout the preimplantation period and the number of oocytes collected were significantly lower with the use of the step-down regimen than during the previous failed cycle in which the standard protocol was used. The fertilization rate was similar and the number of good-quality embryos transferred was comparable. However, the implantation and pregnancy rates were significantly improved in patients who underwent the step-down regimen compared with those who received the standard protocol.

Conclusion(s): With the use of a step-down regimen with FSH in high responders, our clinical results demonstrate that uterine receptivity can be improved when E2 levels are decreased during the preimplantation period.