Morphokinetic Characteristics and Developmental Potential of In Vitro Cultured Embryos from Natural Cycles in Patients with Poor Ovarian Response

Table 3

Comparison of timing of the events in early embryo development between normally developing embryos and embryos with cleavage irregularities.

Morphokinetic parameters	Normally developing embryos	Embryos with cleavage irregularities
	26	27
PB2	258.5 (90.5)	208.9 (88.7)	0.071
PNa	608.6 (214.8)	556.0 (174.9)	0.359
PNf	1460.9 (243.1)	1680.8 (526.7)	0.075
VP (PNf  −  PNa)	856.2 (184.8)	1014.3 (310.3)	0.037
ECC1 (  −  PB2)	1334.1 (143,3)	1610.9 (570.4)	0.096
	1624.2 (225.2)	1813.7 (497.9)	0.093
	2315.4 (211.4)	2472.4 (519.9)	0.256
ECC2	788.3 (173.7)	1064.6 (263.1)	0.005
Dck1	38.4 (42.9)	324.5 (656.5)	0.032
S2 ()	91.5 (152.3)	338.4 (361.2)	0.015

Note: mean time values are in minutes, SD in parentheses. PB2: time passed from ICSI to the extrusion of the second polar body; PNa: time from ICSI to the appearance of the both pronuclei; PNf: time from ICSI to the disappearance of the pronuclei; VP: time period until the pronuclei become visible; ECC1 = −  PB2: the duration of the first cell cycle; : time from ICSI to the first frame in which two, three, and four cells are visible; ECC2 = : the duration of the second embryo cell cycle; dck1: the duration of the first cytokinesis; s2 = : the synchronization of the cell divisions between the 2- and 4-cell stages.