Association of blood progesterone levels on trigger day and low oocyte retrieval in cases with polycystic ovary syndrome undergoing in-vitro fertilization: A prospective cohort study.

Background: The number of follicles aspirated during intracytoplasmic sperm injection (ICSI)/in vitro fertilization (IVF) treatment does not always match the number of oocytes recovered.

Objective: This study aimed to assess the oocyte retrieval rate (ORR) distribution data and investigate the risk factors for low ORR in polycystic ovary syndrome (PCOS) cases undergoing IVF/ICSI.

Materials and methods: This prospective cohort study was conducted on 140 women aged between 18 and 40 yr with PCOS who were referred to Arash hospital in Tehran, Iran for ICSI/IVF treatment from March to November 2024. The ratio of obtained oocytes to follicles ( $\ge$ 17 mm) on the trigger day was used to determine the OPR. 140 women were split into 2 groups: one with a low ORR and one with a normal ORR, each separated by one standard deviation from the ORR mean.

Results: No significant difference was observed between the low and normal ORR groups for progesterone levels. A statistically significant difference was observed in terms of estradiol/follicle ratio above 17, number of follicles above 17, and number of retrieved eggs between the low and normal ORR groups. Logistic regression analysis showed that serum estradiol/follicle ratio ( $\ge$ 17 mm) with (OR = 0.96, 95% CI [0.94-0.98], p = 0.001) was a factor affecting low ORR.

Conclusion: Low ORR, which results in fewer embryos and more cycle cancellations, may be caused by low progesterone levels on the trigger day, low estradiol levels/follicles ( $\ge$ 17 mm), and the use of the progestin-primed regimen in PCOS cases.