Table 2.

Comparison between pregnancy and implantation rates of single FETs using slow frozen or vitrified day 3 embryos

Variable	Slow freeze	Vitrified	P value
No. of cycles	526	485
Maternal age (years)	32.3 ± 4.8	32.3 ± 4.7	>0.05a
No. of transferred embryos	526	485
No. of good quality embryos transferred	366 (69.6 %)	400 (82.5 %)	<0.001b
Pregnancy rates
Overall embryos	184 (35.0 %)	198 (40.8 %)	>0.05b
Good quality embryos	167 (45.6 %)	186 (46.6 %)	>0.05b
Implantation rates
Overall embryos	182 (34.6 %)	174 (35.9 %)	0.671 b
Good quality embryos	165 (45.1 %)	162 (40.5 %)	0.200 b

^aIndependent t test

^bPearson’s chi-square test