Table 2 Characteristics of the true NC-FET
From: Follicular phase length has no influence on frozen-thawed embryo transfers in natural cycles
| Parameters | Prolonged FPL group (n = 127) | Normal FPL group (n = 737) | p value |
|---|---|---|---|
| Ovulation day | 23.0 ± 2.4 (21–33) | 16.0 ± 2.2 (9–20) | <0.001 |
| Embryonal stage at transfer | 0.591 | ||
| Cleavage-stage | 41 (32.3%) | 256 (34.7%) | |
| Blastocyst | 86 (67.7%) | 481 (65.3%) | |
| No. of embryos transferred | 1.52 ± 0.50 (1–2) | 1.50 ± 0.50 (1–2) | 0.651 |
| Cleavage-stage | 1.78 ± 0.42 (1–2) | 1.66 ± 0.48 (1–2) | 0.116 |
| Blastocyst | 1.40 ± .049 (1–2) | 1.41 ± 0.49 (1–2) | 0.750 |
| Optimal embryos transferred | |||
| Cleavage-stage | 65.8% (48/73) | 53.1% (225/424) | 0.044 |
| Blastocyst | 76.7% (92/120) | 69.3% (471/680) | 0.102 |
| Endometrial thickness | 8.64 ± 1.34 (6.1–12.0) | 8.32 ± 1.37 (6.0–13.8) | 0.004 |
| Biochemical pregnancy | 0.086 | ||
| Yes | 80 (63.0%) | 404 (54.8%) | |
| No | 47 (37.0%) | 333 (45.2%) | |
| Clinical pregnancy | 0.043 | ||
| Yes | 78 (61.4%) | 381 (51.7%) | |
| No | 49 (38.6%) | 356 (48.3%) | |
| Implantation rate | 48.2% (93/193) | 41.9% (463/1104) | 0.106 |
| Miscarriage rate | 7.7% (6/78) | 13.1% (50/381) | 0.182 |