Table 1.
Characteristics of single embryo transfer cycles by day of blastocyst cryopreservation
| Day 5 SET | Day 6 SET | p value | |
|---|---|---|---|
| Age at time of cryopreservation, years | 32.11 ± 2.88 | 32.42 ± 2.89 | 0.26 |
| Age at time of ET, years | 33.49 ± 3.22 | 34.01 ± 3.14 | 0.08 |
| BMI, kg/m2 | 26.31 ± 6.05 | 26.18 ± 5.96 | 0.82 |
| AMH, ng/mL | 5.23 ± 6.71 | 4.03 ± 3.91 | 0.07 |
| Multiparous, n (%) | 168 (64.4) | 132 (63.8) | 0.92 |
| Total frozen ET cycles, n | 261 | 207 | 0.08 |
| <35 years old | 205 (78.5) | 148 (71.5) | |
| 35–37 years old | 56 (21.5) | 59 (28.5) | |
| Endometrial preparation, n (%) | 0.98 | ||
| Natural with luteal progesterone | 57 (21.8) | 45 (21.7) | |
| Programmed | 204 (78.2) | 162 (78.3) | |
| Cryopreservation technique, n (%) | 0.02 | ||
| Slow freeze | 170 (65.1) | 156 (75.4) | |
| Vitrification | 91 (34.9) | 51 (24.6) | |
| Cycles following “Freeze all” n (%) | 22 (8.4) | 5 (2.4) | 0.01 |
| Elective or obligatory SET n (%) | |||
| Elective | 186 (71.3) | 82 (39.6) | <0.01 |
| Obligatory | 75 (28.7) | 125 (60.4) | |