Effect of Gonadotropin Dose Reduction during Controlled Ovarian Hyperstimulation on Progesterone Levels and Embryo Outcomes in Women Undergoing IVF/ICSI-ET with GnRH-A Protocol.

Objectives: This study investigates the impact of reduced gonadotropin doses during controlled ovarian hyperstimulation (COH) on progesterone levels in the late follicular phase of IVF/ICSI-ET.

Design: This was a retrospective cohort study employing propensity score matching to balance groups. Participants/Materials: This study enrolled infertile patients undergoing IVF/ICSI-ET at the Reproductive Medicine Center of the 900th Hospital from January 2017 to July 2020.

Setting: This study was carried out at the Reproductive Medicine Center, 900th Hospital of PLA Joint Logistic Support Force, formerly Fuzhou General Hospital.

Methods: A total of 1,380 patients were enrolled; 670 received reduced gonadotropin doses (12.5-75 units/day from days 6 to 8), and 710 underwent routine treatment. The primary outcome measured was progesterone levels on trigger day.

Results: Progesterone levels on trigger day were significantly lower in the gonadotropin dose reduction group (1.24 ± 0.51) compared to the control group (1.34 ± 0.53, p < 0.001). The proportion of patients with P ≥1.5 ng/mL was significantly lower in the gonadotropin dose reduction group compared to the control group (22.7% vs. 29.9%, p = 0.003). Multivariable logistic regression indicated that dose reduction decreased the risk of progesterone elevation (OR = 0.535, 95% CI: 0.404-0.709).

Limitations: The study is limited by its retrospective design, which may introduce biases.

Conclusions: Reducing gonadotropin doses during COH may lower elevated progesterone levels in the late follicular phase, potentially improving embryo outcomes in IVF/ICSI-ET.