Ratio between inner cell mass diameter and blastocyst diameter is correlated with successful pregnancy outcomes of single blastocyst transfers

Objective: To evaluate the ability to predict pregnancy outcomes of single-blastocyst transfers by measuring the ratio of inner cell mass (ICM) diameter to blastocyst diameter using time-lapse images. Design: Retrospective cohort study. Setting: University-affiliated medical center. Patient(s): One hundred twenty-seven women undergoing a total of 129 blastocyst transfers with intracytoplasmic sperm injection. Intervention(s): Embryo monitoring by time-lapse microscopy. Main Outcome Measure(s): The ratio of ICM diameter to blastocyst diameter in single-blastocyst transfers and clinical pregnancy rates. Result(s): In phase I of the study, 63 women underwent 65 single blastocyst transfers that resulted in 25 pregnancies (40% of thewomen). The successfully implanted blastocysts had an average ICM/blastocyst diameter ratio of 0.487 +/- 0.086, whereas the average ICM/blastocyst ratio of nonimplanted blastocysts was significantly lower (0.337 +/- 0.086). The live-birth rate was 29%(18/63). In phase II, 64 single-blastocyst transfers were performed in 64 women. The ICM/blastocyst diameter ratio was measured, and blastocysts with the highest ratios were chosen for transfer. Forty-three women (67%) with an average ICM/blastocyst diameter ratio of 0.46 achieved pregnancy, and 36 of the 43 pregnancies (84%) resulted in the delivery of a healthy baby. In the 21 women (33%) who failed to achieve pregnancy, the average ICM/blastocyst ratio was 0.45. The resultant positive predictive value was 74%, and the negative predictive value was 70%. Conclusion(s): The ICM-to-blastocyst diameter ratio is a predictor of implantation and live birth in single-blastocyst transfers, offering a simple, noninterfering method to select blastocysts with high developmental capacity. (C) 2016 by American Society for Reproductive Medicine.