Table 1 Baseline characteristics in fresh ET and FET groups
Characteristics | Fresh ET (n = 5216) | FET (n = 2598) | P |
|---|---|---|---|
Age at egg retrieval (year) | 29.55 ± 2.86 | 28.96 ± 2.99 | < 0.001 |
BMI (kg/m2) | 21.80 ± 2.74 | 21.74 ± 2.91 | 0.083 |
Infertility duration (year) | 4.64 ± 3.07 | 4.43 ± 2.88 | 0.021 |
AMH (ng/ml) | 3.26 ± 2.54 | 5.58 ± 3.64 | < 0.001 |
Basal FSH (mIU/ml) | 5.64 ± 0.03 | 5.04 ± 0.03 | < 0.001 |
Primary infertility, n (%) | 2522 (48.4) | 1326 (51.0) | 0.044 |
Primary cause of infertility |  |  | < 0.001 |
 Pelvic and tubal factor, n (%) | 4236 (70.2) | 2040 (61.5) |  |
 Male, n (%) | 645 (12.4) | 401 (15.4) |  |
 Unexplained, n (%) | 234 (4.5) | 125 (4.8) |  |
 Ovulatory obstacle, n (%) | 37 (6.5) | 14 (13.4) |  |
 Endometriosis, n (%) | 60 (6.4) | 18 (4.8) |  |