Table 2.

Multivariate analysis showing the effect on LBR of fresh versus frozen cycle, age, embryo quality, fertilization method, and cumulative ET and BMI

	Odds ratio	Standard error	z	P $>$ |z|	[95% CI]
Cycle type (fresh ET vs FET)	0.7625669	0.0447572	-4.62	0.000	0.6797021	0.8555341
Age	0.9144266	0.0054659	-14.97	0.000	0.9037761	0.9252027
Syngamy (EC, NEBD or 2PN)	0.7656162	0.0281109	-7.27	0.000	0.7124557	0.8227434
Cell number on day 2	1.1618480	0.0441235	3.95	0.000	1.0785080	1.2516290
Embryo grade on day 2	0.7765594	0.0283183	-6.93	0.000	0.7229937	0.8340938
Fertilization method (IVF vs ICSI)	0.8910954	0.0505859	-2.03	0.042	0.7972655	0.9959681
Cumulative ET	0.9443254	0.0288636	-1.87	0.061	0.8894150	1.0026260
BMI	0.9926360	0.0057259	-1.28	0.200	0.9814767	1.0039220
Multivariate analysis was undertaken using logistic regression. Syngamy check was the first evaluation performed 23-24 hr after insemination/ICSI when the embryos were assessed for the presence and number of cells (EC = early cleavage, NEBD = nuclear envelope breakdown, or 2PN = 2 pro-nuclei). Embryos were evaluated again on day 2 post insemination/ICSI. Number of cells, degree of fragmentation, and multinucleation (grading of embryos) were assessed at the day 2 check. Cumulative ET (embryo transfer) refers to previous embryo transfer cycles included in the analysis