Table 3. Demographic and clinical data.
Study Group
(double vitrification)
Control Group
(single vitrification)
p-value
Transferred blastocysts (n) 381 780
Embryo transfers (n) 252 450
Positive βHCG 46%
(116/252)
63.3%
(285/450)
0.016
Clinical pregnancy rate 34.9%
(88/252)
52.2%
(235/450)
0.006
Ongoing pregnancy rate 31.3%
(79/252)
47.3%
(213/450)
0.012
Live birth rate 30.2%
(76/252)
45.6%
(205/450)
0.021
Biochemical pregnancy rate 24.1%
(28/116)
17.9%
(51/285)
0.248
Miscarriage rate 10.2%
(9/88)
9.4%
(22/235)
0.894
Newborns (n) 80 212
Mean birthweight (gr) 2950 2837 0.459