Mean blastomere diameter may predict clinical pregnancy in long agonist protocol intracytoplasmic sperm injection cycles with single embryo transfer

The main purpose of this study was to investigate the effect of mean blastomere diameter (MBD) on pregnancy rates in in vitro fertilization (IVF) cases undergoing the long agonist cycle protocol. A total of 84 cases were evaluated within the scope of this observational prospective study. All cases were normoresponders, under 35 years old, with the long agonist protocol applied and single embryo (grade I or II) transfer performed. On the third day after ICSI, each embryo selected for transfer was subjected to measurement of the mean blastomere diameter (MBD) at ×25 magnification. The mean female age was 30.14 ± 3.32 years, and the total clinical pregnancy rate was 33.3%. In the group that got pregnant, MBD was found to be statistically significantly higher than in the nonpregnant group. In terms of predicting clinical pregnancy, when the MBD value of 49.73 μm was accepted as the best cutoff value, the sensitivity was calculated as 75% and specificity as 53.6%. Clinical pregnancy rate was 18.9% in cases below this value, whereas clinical pregnancy rate was 44.7% in cases with this value and above. In other words, when the MBD value rose above 49.73 μm from a value below 49.73 μm, the clinical pregnancy rate increased by an average of 2.3 times. With MBD measurement, it is possible to select the embryo with the best implantation capability in microinjection cycles with the long luteal agonist protocol.