Table 3. Factors associated with the occurrence of clinical pregnancy evaluated by binary logistic regression model.
Variable Implantation rate p-value
Up to50%
(n=451)
> 50%
(n=161)
n (%) n (%)
AGE RANGE
≤ 35 years
From 36 to 40 years
≥ 41 years

231 (51.2)
148 (32.8)
72 (16.0)

93 (57.8)
65 (40.4)
3 (1.9)
<0.001Q
EMBRYO TRANSFER STAGE
Cleavage
Blastocyst

310 (68.7)
141 (31.3)

40 (24.8)
121 (75.2)
<0.001Q
FREEZING TIME
0 to 90 days*
91 to 180 days
181 to 360 days*
> 360 days*

252 (55.9)
77 (17.1)
52 (11.5)
70 (15.5)

110 (68.3)
26 (16.1)
12 (7.5)
13 (8.1)
0.019Q
NUMBER EMBRYOS TRANSFER
1
2
3
4

0 (0.0)
312 (93.1)
115 (84.6)
25 (96.2)

116 (100.0)
23 (6.9)
21 (15.4)
1 (3.8)
<0.001W

Q Chi-square test, W Wilcoxon Mann-Whitney test.
* Statistically significant difference in implantation rate compared to the 0-90 days group (Tukey post hoc test, p<0.05).