Progesterone Elevation on the Day of Triggering Final Oocyte Maturation Is Associated With Decreased Oocyte and Embryo Quality in Low Responders

BACKGROUND: Progesterone elevation (PE) is perceived as the product of cumulative secretion of low levels of progesterone from multiple developing follicles and is commonly present in high responders. Therefore, PE occurring with an unexpectedly low number of follicles potentially represents a different pathophysiological entity such as follicular dysregulation, which may reflect poorer follicular and oocyte quality, which is not yet well studied. AIM: To determine if progesterone elevation is associated with oocyte or embryo quality in patients with 1-4 follicles ≥ 10 mm on the day of triggering final oocyte maturation. METHODS: This is a multi-centre retrospective cohort study of 1393 IVF/ICSI cycles with a low response (1-4 follicles ≥ 10 mm) to ovarian stimulation performed from January 2018 to April 2022. Unexpected PE was defined as serum progesterone levels > 4.77 nmol/L on the day of triggering final oocyte maturation. The primary outcome was the number of usable Day 5 blastocysts. Generalised estimating equations were used to account for the clustered nature of data and to adjust for the effect of multiple confounders. RESULTS: A negative association of PE with the primary outcome measure of this study was shown in the multivariable regression analysis where the number of usable blastocysts was significantly (p < 0.0001) lower in the PE group (adjusted mean 0.18, 95% CI 0.07-0.28) compared to the non-PE group (adjusted mean 0.27, 95% CI 0.24-0.31) after adjusting for confounders. CONCLUSION: PE on day of triggering final oocyte maturation is negatively associated with fertilisation rates and the number of usable blastocysts in patients with 1-4 follicles ≥ 10 mm.