Table 5.
Non-prespecified outcomes for cumulative live births including the long-term follow-up cohort (Intention-to-Treat Analysis)a
| Outcomes, No./total (%) | Blastocyst-stage embryo transfer group (n = 497) | Cleavage-stage embryo transfer group (n = 495) | Absolute difference (95% CI)b | Relative risk (95% CI) | P valuec |
|---|---|---|---|---|---|
| Cumulative live births | 402 (80.9%) | 384 (77.6%) | 3.3% (−1.7 to 8.4) | 1.04 (0.98 to 1.11) | 0.199 |
| Singleton live births | 391 (78.7%) | 375 (75.8%) | 2.9% (−2.3 to 8.1) | 1.04 (0.97 to 1.11) | 0.274 |
| All twin live births | 11 (2.2%) | 9 (1.8%) | 0.4% (−1.4 to 2.1) | 1.22 (0.51 to 2.91) | 0.658 |
| No. of unused frozen embryos, mean (SD) | 3.9 (3.4) | 5.2 (4.1) | −1.3 (−1.8 to −0.9) | - | 3.87e-08 |
| No. of unused frozen embryos in women with a live birth, mean (SD) | 4.5 (3.3) | 5.9 (4.0) | −1.4 (−1.9 to −0.9) | - | 1.03e-07 |
| No. of unused frozen embryos in women without a live birth, mean (SD) | 1.2 (1.9) | 2.8 (3.8) | −1.6 (−2.4 to −0.7) | - | 0.00035 |
| No. of women without a frozen embryo | 89 (17.9%) | 65 (13.1%) | 4.8% (0.3 to 9.3) | 1.36 (1.02 to 1.83) | 0.038 |
| No. of women without a frozen embryo without a livebirth | 58 (11.7%) | 53 (10.7%) | 1.0% (−3.0 to 4.9) | 1.09 (0.77 to 1.55) | 0.631 |
| No. of women without a frozen embryo with a livebirth | 31 (6.2%) | 12 (2.4%) | 3.8% (1.3 to 6.3) | 2.57 (1.34 to 4.95) | 0.003 |
Non-inferiority P value = 1.16e-07 for cumulative live births (with margin = −0.1, α = 0.025, one-sided).
SD standard deviation.
aThis is a secondary, post-hoc analysis of the long-term follow-ups from randomization day to July 28th, 2023, and treatment after the study period (1 year of randomization) did not follow our prespecified protocol, reflecting real-world practice.
bAbsolute differences in percentages are indicated in percentage points, and absolute differences in other values are indicated in units of that value.
cAll P values are for superiority, two-sided. No adjustments were made for multiple comparisons. Two-sample t-test was used for continuous data; Chi-square test was used for categorical data.