Table 1.
Baseline information and stimulation and frozen FET cycle characteristics, by timing of FET
| Immediate, n = 80 | Delayed, n = 264 | p value | |
|---|---|---|---|
| Median days between VOR and FET (range) | 37 (23–78) | 69 (51–120) | |
| BMI | 25.16 ± 5.12 | 26.41 ± 5.86 | 0.09 |
| Age at oocyte retrieval | 33.65 ± 3.78 | 33.52 ± 3.77 | 0.79 |
| Baseline FSH | 6.48 ± 2.53 | 6.00 ± 2.24 | 0.10 |
| Median AMH (IQR) | 3.94 (2.85–5.38) | 3.02 (1.60–5.18) | 0.19 |
| GnRH antagonist stimulation protocol | 70 (87.3) | 202 (76.5) | 0.06 |
| Peak E2 in fresh cycle | 2384 ± 1197 | 2606 ± 1324 | 0.18 |
| Total oocytes retrieved | 16.98 ± 8.65 | 18.33 ± 9.55 | 0.26 |
| Total embryos cryopreserved | 4.14 ± 4.10 | 4.50 ± 3.35 | 0.43 |
| PGS performed, n (%) | 24 (30.0) | 91 (34.5) | 0.46 |
| Freeze-only in fresh cycle, n (%) | 59 (73.8) | 167 (63.3) | 0.08 |
| Trigger medication, n (%) | 0.73 | ||
| hCG | 48 (60.0) | 160 (60.6) | |
| GnRH agonist | 27 (33.8) | 93 (35.2) | |
| Dual trigger | 5 (6.3) | 11 (4.2) | |
| Endometrial preparation, n (%) | < 0.01 | ||
| Natural | 58 (72.5) | 96 (36.4) | |
| Programmed | 22 (27.5) | 168 (63.6) | |
| Number embryos transferred | 1.4 ± 0.49 | 1.48 ± 0.53 | 0.23 |