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

Tung Nguyen Thanh,1,* Duc Minh Nguyen,2,* Tuan Dinh Le,3 Lan Ngoc Do,1 Son Tien Nguyen,3 Phuong Nguyen Minh,1 Phong Nguyen Van,4 Tien Minh Bui,5 Tuyen Thanh Thi Bui,5 Hung Nguyen Dao,6 Kien Trung Nguyen5 1Military Institute of Clinical Embryology and Histology, Vietnam Military Medical University, Hanoi, 10000, Vietnam; 2Andrology and Fertility Hospital of Hanoi, Hanoi, 10000, Vietnam; 3Department of Rheumatology and Endocrinology, Military Hospital 103, Vietnam Military Medical University, Hanoi, 10000, Vietnam; 4Department of Biology and Medical Genetics, Vietnam Military Medical University, Hanoi, 10000, Vietnam; 5Department of Obstetrics and Gynecology, Thai Binh University of Medicine and Pharmacy, Thai Binh, 410000, Vietnam; 6Department of Obstetrics and Gynecology, Military Hospital 103, Vietnam Military Medical University, Hanoi, Vietnam*These authors contributed equally to this workCorrespondence: Kien Trung Nguyen, Department of Obstetrics and Gynecology, Thai Binh University of Medicine and Pharmacy, Thai Binh, 410000, Vietnam, Tel +84989281982, Email trungkiendhytb@gmail.comBackground: 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.Keywords: Smooth reticulum endoplasmic cluster, SERc, Intracytoplasmic sperm injection, In vitro fertilization, IVF