Understanding the implications of follicular output rate (FORT) and follicle to oocyte index (FOI) on human embryo morphokinetics

Abstract

Objective To study if there are any effects of follicular output rate (FORT) and follicle to oocyte index (FOI) on embryos morphokinetics. Study design Kinetic data of 8,376 embryos, cultured in a time-lapse imaging incubator, derived from 2,470 patients undergoing ICSI cycles were analysed. Embryos were split into groups according to FOI value: Low FOI (n=247 cycles and 894 embryos) and High FOI (n=2,223 cycles and 7,482 embryos) and according to the FORT value: Low FORT (n= 753 cycle and 2,556 embryos), Medium FORT (n=874 cycles and 2,970 embryos), and High FORT (n=843 cycles and 2,850 embryos). Morphokinetic data were compared among the groups. Results Embryos derived from cycles with a low FOI presented slower development, a significantly lower KID score D5, blastocyst formation, and implantation rates when compared with those from cycles with high FOI. For the FORT, an increased time to complete morphokinetic events, significantly lower rates of blastocyst formation and implantation was observed among embryos derived from cycles with low FORT, followed by those with medium FORT, while embryos derived from cycles with high FORT presented a better development competence. However, no significant differences were noted in clinical pregnancy, miscarriage, or livebirth rates when the low, medium, and high FORT groups were compared. Conclusion FORT and FOI correlate with faster embryo development and may be a valuable approach to predict embryo developmental potential.