The impact of oocytes containing smooth endoplasmic reticulum aggregates on assisted reproductive outcomes: a cohort study

BACKGROUND: The impact of smooth endoplasmic reticulum aggregates (SERa) on assisted reproductive technology (ART) outcomes was still controversial. Our objective is to investigate the impact of the presence of SERa on intracytoplasmic sperm injection (ICSI) outcomes. METHODS: This was a retrospective cohort study. A total of 1,090 fresh ICSI cycles from 944 patients between January 2016 and June 2020 were included. Outcomes from clinical, embryological and neonatal aspects were compared between SERa + and SERa- cycles as well as between SERa + and SERa- oocytes. RESULTS: The total gonadotropin (Gn) dose, number of oocytes retrieved, serum estradiol concentration and number of the available embryo were significantly higher in SERa + cycles than in SERa- cycles (P < 0.05). Comparable two pronuclei (2PN) fertilization rate and poly-pronucleus zygote rate were shown in SERa + and SERa- cycles (P > 0.05), but which were higher in SERa + oocytes than in SERa- oocytes (P < 0.05). No statistical difference in blastocyst formation rate was found in SERa + and SERa- cycles as well as in SERa + and SERa- oocytes (P > 0.05). Good-quality embryo rate was statistically higher in SERa- cycles than in SERa + cycles (P < 0.05), but the difference was comparable between SERa + and SERa- oocytes (P > 0.05). No statistical difference in clinical pregnancy rate, spontaneous abortion rate, live birth rate and premature delivery rate were found in SERa + and SERa- cycles as well as in SERa + and SERa- oocytes (P > 0.05). The implantation rate was comparable in SERa + and SERa- cycles (P > 0.05), but it is higher in the group of only SERa- embryo transfer when compared with the group of mixed SERa + and SERa- embryo transfer (P < 0.05). 159 newborns in SERa + cycles and 140 newborns in SERa- cycles were followed up. Comparable newborn malformation rate was observed between SERa + and SERa- cycles and oocytes (P > 0.05). Logistic regression analysis revealed number of oocytes and total dose of Gn were risk factors for SERa occurrence (aOR = 1.05 and 1.55, P < 0.001). CONCLUSION: Oocyte's SERa is correlated with a number of oocytes retrieved and higher Gn dose, but it does not affect pregnancy outcomes and increase newborn malformation rate. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1186/s12884-022-05141-9.