Does empty zona pellucida indicate poor ovarian response on intra cytoplasmic sperm injection cycles?

The factors behind the empty zona pellucida (EZP) formation and its relationship with in vitro fertilization (IVF) outcomes were analyzed. A total of 104 patients who underwent IVF treatment and collected oocytes including EZP were enrolled in this study. EZP index (EZPI = the ratio of number of EZP to number of cumulus-oocyte complex (COC)) was used for the statistical analysis. Patients were grouped as Group 1 when EZPI ≤ 0.17 (n = 57) and Group 2 when EZPI > 0.17 (n = 47). Type-2 EZP, a variation or an advanced type of oocyte degeneration, is tested. Woman age, basal hormone levels, and total gonadotropin dose were significantly higher in Group 2 compared to Group 1. Total antral follicle count was significantly low in Group 2. Total number of mature oocytes, oocyte quality index, the number of fertilized oocytes, and the numbers of Grade 1 embryos were significantly low in Group 2. On the linear regression analysis, using gonadotropin releasing hormone antagonist protocol (B = 0.086, p = 0.030), the number of ≥17 mm follicle (B = 0.015, p = 0.047), peak serum level of estradiol (B = -3.625; p = 0.014), number of fertilized oocytes (B = -0.02, p = 0.0001) and the day-2 embryo score (B = -0,044, p = 0.001) significantly affected EZPI. An increment of the EZPI may be revealed decreased oocyte quality, and it is also related to the poor ovarian response.