Intermediate and normal sized CGG repeat on the FMR1 gene does not negatively affect donor ovarian response

Area of Science:

• Reproductive endocrinology
• Human genetics
• Assisted reproductive technology

Background:

• Fragile X syndrome is linked to diminished ovarian reserve and poor response to stimulation.
• The fragile X mental retardation 1 (FMR1) gene contains CGG repeats that may influence ovarian function.

Purpose of the Study:

• To evaluate the predictive value of CGG repeats on the FMR1 gene for ovarian response to gonadotropins.
• To assess the impact of CGG repeats on clinical outcomes in an oocyte donation program.

Main Methods:

• 204 oocyte donor candidates were screened for FMR1 CGG repeats, categorized into controls and cases (35-45 repeats, >45 repeats).
• All participants underwent ovarian stimulation with a GnRH antagonist protocol and GnRH agonist trigger.
• Outcomes measured included oocyte yield, stimulation duration, gonadotropin dosage, and pregnancy rates.

Main Results:

• No significant differences in oocyte yields or stimulation days were observed between groups.
• The control group required higher gonadotropin dosages compared to the study group.
• CGG repeat status did not affect biochemical pregnancy, ongoing pregnancy, or miscarriage rates.

Conclusions:

• Intermediate CGG repeats on the FMR1 gene do not negatively impact ovarian stimulation or clinical outcomes in oocyte donation.
• Fragile X genetic screening is not recommended for predicting ovarian stimulation response.
• Findings contrast with previous studies in infertility patients, highlighting the importance of context in oocyte donation programs.