Research progress on the effect of oocyte smooth endoplasmic reticulum clusters on early embryo development and pregnancy outcome

With the clinical development and application of intracytoplasmic sperm injection(ICSI)technology in human assisted reproduction,the influence of oocyte quality on embryo development has been paid more and more attention.So far,there have been many reports on oocyte morphology affecting embryo development.It has been found in some works that the appearance of smooth endoplasmic reticulum clusters(SERC)in oocytes may affect the fertilization and embryo development of oocytes.However,with the increasing reports of SERC-containing oocytes obtained by in vitro fertilization and healthy offspring in recent years,there is still some controversy on whether to continue to use SERC-containing oocytes for the following assisted reproductive therapy in clinical practice.Based on this,this review aims to review the research progress of SERC in oocytes in recent years.

Real value oftheoocyteswith 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/ICSl)treatments at the Center of Reproductive Medicine,First Affliated 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 ICSl 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.