Morphokinetic characteristics of embryos derived from in-vitro-matured oocytes and their in-vivo-matured siblings after ovarian stimulation

Abstract Research question Does delayed maturation of aspirated metaphase I (MI) oocytes, completed in vitro , adversely affect early embryo development? Design Time-lapse microscopy was used to compare morphokinetic variables between embryos derived from oocytes with delayed maturation after ovarian stimulation and from in-vivo-matured metaphase II (MII) sibling oocytes from the same IVF and intracytoplasmic sperm injection cycle. Results A total of 1545 injected oocytes in 169 cycles from 149 patients were included. The in-vitro-matured oocytes had lower normal fertilization rates than the MII aspirated oocytes (50.2% versus 68.0%; P P P P Conclusions Embryos derived from oocytes that failed to mature in-vivo in standard treatment after ovarian stimulation may show a different morphokinetic profile from their sibling oocytes aspirated at the MII stage after completing maturation in-vivo .