The Relationship Between Smooth Endoplasmic Reticulum Clusters in Metaphase II Oocytes and Embryological and Birth Outcomes in Infertile Couples.

Background: To assess the relationship between oocytes with smooth endoplasmic reticulum cluster (SERc) and embryological and birth outcomes in infertile couples.

Methods: This was a descriptive study that included 231 infertile patients undergoing in vitro fertilization (IVF) with a total of 2447 mature oocytes (MII), of which 279 oocytes with SERc(+) from 100 patients, the remaining 2168 oocytes with SERc(-). Oocytes were evaluated for the presence or absence of the SERc simultaneously with intracytoplasmic sperm injection at 200x magnification using inverted microscopy - Observe D1.

Results: The mean age of patients was 32.05 ± 5.56 years. One hundred patients had at least one SERc(+) oocyte (with 279 SERc(+) and 956 SERc(-) oocytes). One hundred and thirty-one patients had 1212 SERc(-) oocytes. Fertilization outcomes and the rates of good-quality embryos on day 2 and day 5 did not differ between the SERc(+) and the SERc(-) groups. In the first frozen embryo transfer cycles, the clinical pregnancy rate in the group of patients with SERc(+) was not different with the SERc(-) group (61.1% vs 48.78%, p = 0.074, respectively). The live birth rate in the SERc(+) group was statistically significantly higher than the SERc(-) group (57.7% vs 43.9%, p = 0.045, respectively).

Conclusion: The fertilization rate, the quality of embryos on days 2 and 5 from oocytes with SERc(+) are similar to those with SERc(-). The live birth rate in the patients with SERc(+) group is statistically significantly higher than the SERc(-) group. There is no difference in clinical pregnancy rate between patients with and without SERc. Therefore, the exclusion of oocytes with SERc should not be recommended.