TABLE 5.

Overview of hourly averages.

	Pregnancy after ET after 2PN vitrification-warming n = 182 (38.9%)	No pregnancy after ET after 2PN vitrification-warming n = 286 (61.1%)	p-value
Vitrification time a	n = 182	n = 286
Mean in hours (±σ)	18.74 (±.63)	18.62 (±.64)	.038
Group A (n = 130)	n = 40	n = 90
Mean in hours (±σ)	17.94 (±.17)	17.91 (±.26)	.816
Group B (n = 281)	n = 115	n = 166
Mean in hours (±σ)	18.77 (±.25)	18.78 (±.25)	.838
Group C (n = 57)	n = 27	n = 30
Mean in hours (±σ)	19.77 (±.31)	19.85 (±.40)	.567

ET, embryo transfer.

Wilcoxon-Mann-Whitney test for difference between the means.

^a Continuous variable.

Group A: Vitrification time 17:00—18:00 hpi, B: Vitrification time 18:01—19:00 hpi, C: Vitrification time 19:01—21:00 hpi.