Objective:

To explore the factors associated with elevated serum progesterone (P) levels on the day of hCG administration in patients undergoing controlled ovarian stimulation using a gonadotropin-releasing hormone antagonist (GnRH-A) protocol, with implications for clinical practice.

Key Findings:

• Oocyte retrieval age, BMI, basal FSH, and hCG-day serum LH levels were significantly higher in the NP group than in the HP group (p < 0.05).
• Basal progesterone, antral follicle count, hCG-day serum E2, AMH, and total number of oocytes retrieved were significantly lower in the HP group (p < 0.05).
• Multivariate analysis identified BMI, basal P, hCG-day serum E2, hCG-day serum LH, and total oocytes retrieved as independent influencing factors for elevated progesterone levels (p < 0.05).

Interpretation:

Basal progesterone, hCG-day serum E2 and LH levels, and total number of oocytes retrieved are independent risk factors for elevated progesterone levels on hCG day, while BMI serves as a protective factor, highlighting the need for clinical awareness.

Limitations:

• The study is retrospective and may be subject to selection bias, which could affect the generalizability of the findings.
• Exclusion criteria may limit the applicability of the results to broader patient populations.

Conclusion:

The study underscores the importance of specific clinical and endocrine parameters in predicting elevated serum progesterone levels on hCG day during GnRH antagonist treatment cycles, with potential implications for improving clinical outcomes.