Is there a preferred time interval between gonadotropin-releasing hormone (GnRH) agonist trigger and oocyte retrieval in GnRH antagonist cycles? A retrospective cohort of planned fertility preservation cycles.

BACKGROUND: The ideal time frame between gonadotropin-releasing hormone (GnRH) agonist (GnRHa) trigger administration and oocyte retrieval in GnRH antagonist cycles has not been well studied. Our goal was to evaluate the effect of this time interval on oocyte yield and oocyte maturation rate in GnRH antagonist cycles designated for non-medical ("planned") oocyte cryopreservation.

METHODS: We conducted a retrospective cohort study including patients who underwent elective fertility preservation, using the GnRH antagonist protocol and exclusively triggered by GnRH-agonist. We focused on the effect of the trigger-to-retrieval time interval on oocyte yield and maturation rate, while also incorporating age, body mass index (BMI), anti-Müllerian hormone (AMH) levels, basal Follicle-Stimulating Hormone (FSH) levels, as well as the type and dosage of gonadotropin FSH medication.

RESULTS: 438 cycles were included. Trigger-to-retrieval time interval ranged from 32.03 to 39.92 h. The mean oocyte yield showed no statistically significant difference when comparing retrievals < 36 h (n = 240, 11.86 ± 8.6) to those triggered at ≥ 36 h (n = 198, 12.24 ± 7.73) (P = 0.6). Upon dividing the cohort into four-time quartiles, no significant differences in the number of retrieved oocytes were observed (P = 0.54). Multivariate regression analysis failed to reveal any significant associations between the interval and the aforementioned variables.

CONCLUSIONS: The GnRHa trigger to oocyte retrieval interval range in our cohort did not significantly affect oocyte yield and maturation rate.