<b><i>Aim:</i></b> To evaluate the effect of large follicular size (≥24 mm) at day of oocyte retrieval on oocyte/embryo quality. <b><i>Patients and Methods:</i></b> A cohort study was conducted in a single tertiary medical center between July 2018 and May 2019. Before ultrasound-guided follicular aspiration, follicles were measured and divided into 2 groups according to their maximal dimensional size: large: ≥24 mm and normal: <24 mm. Microscopic examination of the follicular aspirates was performed by an embryologist. Each follicle aspirated was evaluated for oocyte maturation, oocyte fertilization, and embryo quality. <b><i>Results:</i></b> 428 follicles were measured, including 383 (62.81%) in the normal and 45 (14.06%) in the large follicle groups. Oocytes were achieved during aspiration from 297 (75.5%) and 29 (64.4%) of the normal and large follicle groups, respectively (<i>p</i> = 0.05). No in-between group differences were observed in mature oocyte (MII), fertilization, and top-quality embryo (TQE) rates. Nevertheless, once a zygote (2PN) was achieved, a trend toward a higher TQE rate/2PN was found in the large follicle group (16/19 [84.2%] vs. 115/171 [67.3%]; <i>p</i> = 0.062). <b><i>Conclusion:</i></b> While a nonsignificant decrease in oocyte recovery rate was found in follicles ≥24 mm, the zygote and TQE per follicle were comparable.
Sperm modulate uterine immune parameters relevant to embryo implantation and reproductive success in mice
