Influencing factors and effects of low oocyte retrieval in patients with polycystic ovary syndrome undergoing in-vitro fertilization

•E2 level/follicle (≥12 mm) on the trigger day could predict low oocyte retrieval events in patients with PCOS.•Low oocyte retrieval may not affect oocyte and embryo developmental potential.•Low oocyte retrieval may increase the risk of no embryo available for transfer. To investigate influencing factors and effects of low oocyte retrieval in patients with polycystic ovary syndrome (PCOS) undergoing in-vitro fertilization (IVF). In total, 720 patients with PCOS undergoing IVF were enrolled in this retrospective study from January 2017 to December 2022. The oocyte retrieval rate (ORR) was defined as the ratio of the number of oocytes retrieved to the number of follicles ≥ 12 mm in diameter on the trigger day. Using 1 standard deviation from the mean ORR as the boundary value, patients were divided into low and normal ORR groups. Patient characteristics, stimulation protocols, serum hormone levels, oocyte maturity, embryo developmental quality, and pregnancy outcomes of fresh transfer cycles were analysed. ORR ranged from 0.06 to 2.69, with a mean value of 1.02. Compared with the normal ORR group (ORR ≥ 0.65), patients in the low ORR group (ORR