Real value of the oocytes with smooth endoplasmic reticulum aggregates in in vitro fertilization/intracytoplasmic sperm injection cycle: a retrospective cohort study

Objective: The management of oocytes affected by smooth endoplasmic reticulum aggregates (SERa) remains debatable. To understand how to manage SERa+ oocytes and cycles, we performed a retrospective cohort study and analyzed the impact of SERa+ cycles and oocytes on clinical and neonatal outcomes. Methods: We included 4856 cycles (149 SERa+ and 4707 SERa-) from 4201 women (age: 21-42 years) who received in vitro fertilization/intracytoplasmic sperm injection (IVF/ICSI) treatments at the Center of Reproductive Medicine, First Affiliated Hospital of Army Military University, from 2016 to 2019. SERa+ cycles had at least one SERa oocyte in the oocyte cohort. All 1722 oocytes in the SERa+ cycle were divided into SERa+ (405) and SERa- (1317) oocytes. Results: The rates of two pronuclei (2PN) and high-quality embryos were lower in SERa+ cycles than in SERa- cycles, regardless of IVF or ICSI (P <0.05). As the proportion of SERa+ oocytes increased in the SERa+ cycles, the rate of high-quality embryos declined gradually (P <0.05). Furthermore, the rate of 2PN in SERa+ oocytes was significantly lower than that in SERa- oocytes (P <0.05). Regardless of whether IVF or ICSI insemination was performed, no significant differences in terms of clinical pregnancy rate and spontaneous abortion rate were observed between SERa+ and SERa- cycles or between SERa+ and SERa- oocytes (P >0.05). Conclusion: Normal fertilization with SERa+ cycles and oocytes was substantially reduced, regardless of the insemination method. Embryos originating from SERa+ oocytes can be transferred when there are no other options, but fully informed consent and strict follow-up of fetal development are mandatory.