Purpose: To analyze the three pro-nuclei (3PN) incidence on clinical outcomes of patients with lower retrieved oocytes in the fresh cleavage-stage embryo transfer (ET) cycles.
Methods: This study included 1200 fresh cleavage-stage ET cycles from January 2013 to June 2015. The patients were divided into 3PN = 0% (773 cycles) and 3PN > 0% (427 cycles) group. Main outcomes compared were fertilization, cleavage, normal fertilization, good quality embryo, implantation, clinical pregnancy, and early abortion rate.
Results: We observed that there was no significant difference in female's age, the number of retrieved oocytes, the number of transferred embryos, the number of good quality embryos, endometrial thickness, infertile time, basal serum follicle-stimulating hormone, and E2 value between two groups (p > 0.05). The fertilization (89.43 versus 83.90%, p < 0.001) and cleavage (98.34 versus 97.19%, p = 0.048) rates were significantly higher in 3PN > 0% than 3PN = 0% group. However, the normal fertilization (70.05 versus 50.67%, p < 0.001), good quality embryos (37.11 versus 26.47%, p < 0.001), and clinical pregnancy (49.81 versus 43.79%, p = 0.046) rates were significantly higher in 3PN = 0% than 3PN > 0% group. The implantation (35.88 versus 33.78%, p = 0.333) and early abortion (8.83 versus 10.70%, p = 0.474) rates were not significantly different between two groups.
Conclusion: 3PN incidence might make a negative effect on clinical outcomes for patients with lower retrieved oocytes in the fresh cleavage-stage ET cycles.
Keywords: 3PN; Cleavage-stage embryo; clinical outcomes.