Table 1. Characterization of the general sample and according to the occurrence of clinical pregnancy.
Variable PREGNANCY
Sample
(n=1568)
Yes
(n=612)
No
(n=956)
p-value
n (%) n (%) n (%)
AGE RANGE
≤ 35 years
From 36-40 years
≥41 years

757 (48.3)
573 (36.5)
238 (15.2)

324 (52.9)
213 (34.8)
75 (12.3)

433 (45.3)
360 (37.7)
163 (17.1)
0.004Q
EMBRYO TRANSFER STAGE
Cleavage
Blastocyst

1.022 (65.2)
546 (34.8)

350 (57.2)
262 (42.8)

672 (70.3)
284 (29.7)
<0.001Q
FREEZING TIME
0 to 90 days
91 to 180 days
181 to 360 days
> 360 days

844 (53.8)
304 (19.4)
172 (11.0)
248 (15.8)

362 (59.2)
103 (16.8)
64 (10.5)
83 (13.6)

482 (50.4)
201 (21.0)
08 (11.3)
165 (17.3)
0.007Q
Number of embryos transfer 1.96±0.71 [2.00] 2.11±0.75 [2.00] 1.87±0.66 [2.00] <0.001W

Q Chi-square test, W Wilcoxon Mann-Whitney test.