Morphokinetic characteristics of embryos derived from in-vitro-matured oocytes and their in-vivo-matured siblings after ovarian stimulation
Margalit, T.; Ben-Haroush, A.; Garor, R.; Kotler, N.; Shefer, D.; Krasilnikov, N.; Tzabari, M.; Oron, G.; Shufaro, Y.; Sapir, O.
Reproductive Biomedicine Online 38(1): 7-11
Does delayed maturation of aspirated metaphase I (MI) oocytes, completed in vitro, adversely affect early embryo development? 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. 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 < 0.001). Early key developmental events were significantly delayed in the normally fertilized in-vitro-matured compared with in-vivo-matured oocytes (polar body extrusion: 5.4 ± 3 versus 3.9 ± 1.8 h; P < 0.001; pronuclear fading: 27.2 ± 4.7 versus 25.1 ± 4.2 h; P < 0.001, respectively) and synchrony of the second cell cycle was adversely affected. The proportions of embryos with optimal second cell cycle length and second cell cycle were similar but with fewer top-quality embryos, based on an algorithm, for the delayed in-vitro-matured oocytes compared with their in-vivo-matured sibling oocytes (14% versus 29.1%; P < 0.001). 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.