Table 1.
Demographic, clinical and IVF treatment characteristics.
| Variables | Naturally conceived | Frozen embryo transfers | ||
|---|---|---|---|---|
| Modified natural cycle | Programmed cycle | P-value | ||
| (n=1334) | (n=217) | (n=635) | ||
| Maternal age (years) | 28.9 (4.8) | 31.1 (5.6) | 30.2 (5.1) | <0.001*** |
| Paternal age (years) | 30.2 (5.4) | 32.2 (6.9) * | 31.4 (6.0) * | <0.001 |
| Maternal BMI (kg/m2) | 20.8 (3.1) | 21.5 (3.9) * | 21.8 (4.1) * | <0.001 |
| Parity (n (%)) | <0.001*** | |||
| • first | 983 (73.7) | 181 (83.4) | 586 (92.3) | |
| • high order | 351 (26.3) | 36 (16.6) | 49 (7.7) | |
| Duration of infertility (m) | 33.0 (27.0) | 34.0 (27.0) | <0.001 | |
| Type of infertility | 0.144 | |||
| • primary infertility | 112 (51.6) | 364 (57.3) | ||
| • secondary infertility | 105 (48.4) | 271 (42.7) | ||
| Cause of infertility | 0.103 | |||
| • female | 105 | 320 | ||
| • male | 28 | 83 | ||
| • mixes | 74 | 209 | ||
| • unexplained | 9 | 66 | ||
| b-AMH (ng/mL) | 3.6 (3.2) | 4.9 (5.3) | 0.859 | |
| Total antral follicle count | 14 (8.75) | 15 (8) | 0.071 | |
| EMT (mm) | 9.7 (2.6) | 9.0 (2.0) | 0.002 | |
| Embryo stage at transfer | 0.863 | |||
| • Cleavage stage | 68 (31.3) | 195 (30.7) | ||
| • blastocyst | 149 (68.7) | 440 (69.3) | ||
| No. of embryos transferred | <0.001 | |||
| • single | 135 (62.2) | 242 (38.1) | ||
| • double | 79 (36.4) | 383 (60.3) | ||
| • triple | 3 (1.4) | 10 (1.6) | ||
BMI, body mass index.
AMH, anti-Müllerian hormone.
E2, serum estradiol.
EMT, endometrial thickness.
Skewed data were presented as median (with interquartile range).
Categorical data was expressed as the number of cases (as a percentage of the total).
P-value <0.05 was considered statistically significant.
*Significantly different from the naturally conceived group.
**Significantly different from the naturally conceived group and natural cycle group.
***Significant differences were found between any two groups.