Table 2.
Comparison of the clinical outcomes from 2 high-quality embryos per transfer.
| ≤35 years (average age 29.92 years) | 36–37 years (average age 36.44 years) | ≥38 years (average age 40.36 years) | P value | |
| Embryo transfer cycles | 3758 | 296 | 318 | |
| Duration of infertility (yrs) | 3.4 ± 0.1 | 5.8 ± 0.8 | 7.8 ± 1.3 | <.001 |
| Embryos from ICSI | 1103 (29.4%) | 77 (26.0%) | 116 (36.5%) | .01 |
| Endometrium thickness (mm) | 9.4 ± 0.0 | 9.3 ± 0.1 | 9.1 ± 0.1 | .026 |
| Pregnancy rate per cycle | 2734 (72.8%) | 174 (58.8%) | 143 (45.0%) | <.001 |
| Implantation rate per cycle | 3831 (51.0%) | 232 (39.2%) | 173 (27.2%) | <.001 |
| Live birth rate per cycle | 2416/3758 (64.3%) | 161/296 (54.4%) | 123/318 (38.7%) | <.001 |
| Multi pregnancy rate (%) | 942/2416 (39.0%) | 48/161 (29.8%) | 24/123 (19.5%) | <.001 |
| Gestational days (d) | 263.1 ± 1.1 | 260.5 ± 5.1 | 268.5 ± 1.4 | .61 |
| Neonatal weight (g) | 2969.8 ± 17.8 | 3141.8 ± 83.3 | 3268.6 ± 86.5 | .001 |
| Preterm birth (<37 wks) | 312/2416 (12.9%) | 22/161 (13.7%) | 13/123 (10.6%) | .713 |
ICSI = intracytoplasmic sperm injection.