Table 5.
Predictors of live birth after elective single embryo transfer (eSET) and double embryo transfer (DET). Figures are numbers (percentages) unless stated otherwise
| Baseline characteristics | Live birth* | Odds ratio (95% CI) | |||
|---|---|---|---|---|---|
| Yes | No | Crude† | Adjusted‡ | ||
| Randomised treatment: | |||||
| DET | 285/466 (61) | 398/900 (44) | 1 | 1 | |
| eSET v DET | 181/466 (39) | 502/900 (56) | 0.50 (0.40 to 0.63)§ | 0.50 (0.39 to 0.63)§ | |
| Mean (SD) age of woman (years) | 31.0 (3.4) | 31.5 (3.5) | 0.97 (0.94 to 1.01) | — | |
| Median (IQR) BMI of woman | 23.5 (21.2-26.0) | 23.2 (21.2-26.4) | 0.99 (0.96 to 1.02) | — | |
| Median (IQR) duration of infertility (years) | 3.0 (2.0-4.0) | 3.1 (2.1-4.4) | 0.96 (0.90 to 1.02) | — | |
| Type of infertility: | |||||
| Primary | 333/454 (73) | 663/884 (75) | 1 | — | |
| Secondary v primary | 121/454 (27) | 221/884 (25) | 1.03 (0.79 to 1.35) | — | |
| Primary cause of infertility: | |||||
| Male | 187/465 (40) | 368/897 (41) | 1 | 1 | |
| Female v male | 108/465 (23) | 239/897 (27) | 0.86 (0.64 to 1.16) | 0.58 (0.38 to 0.88)¶ | |
| Unexplained v male | 96/465 (21) | 154/897 (17) | 1.17 (0.85 to 1.61) | 0.79 (0.51 to 1.22) | |
| Other/mixed v male | 74/465 (16) | 136/897 (15) | 0.99 (0.69 to 1.41) | 0.77 (0.51 to 1.15) | |
| Type of treatment: | |||||
| ICSI | 190/465 (41) | 420/898 (47) | 1 | 1 | |
| IVF v ICSI | 275/465 (59) | 478/898 (53) | 1.25 (0.99 to 1.59)** | 1.66 (1.15 to 2.38)†† | |
| Day of embryo transfer: | |||||
| Day 2 | 366/465 (79) | 712/893 (80) | 1 | — | |
| Day 3 v day 2 | 95/465 (20) | 166/893 (19) | 1.10 (0.70 to 1.74) | — | |
| Day 5 v day 2 | 4/465 (1) | 15/893 (2) | 0.51 (0.17 to 1.58) | — | |
| Median (IQR) No of embryos available for transfer | 5.0 (4.0-8.0) | 5.0 (3.0-7.0) | 1.03 (1.00 to 1.07) | — | |
| Quality of embryos transferred | |||||
| Grade B | 27/450 (6) | 103/848 (12) | 1 | 1 | |
| Grade A v grade B | 423/450 (94) | 745/848 (88) | 1.93 (1.23 to 3.04)†† | 1.99 (1.26 to 3.13)†† | |
SD=standard deviation; IQR=interquartile range; BMI=body mass index; ISCI=intracytoplasmic sperm injection.
*Means (SD) provided for normally distributed data; medians (IQR) presented for skewed data. Denominator differs because of missing values for some characteristics.
†Estimated from separate logistic models adjusted for eSET v DET and trial.
‡One logistic model resulting from stepwise procedure. Adjusted for eSET v DET, trial, embryo grade, type of treatment, primary cause of infertility.
§P≤0.001.
¶0.01<P≤0.05.
**0.05<P≤0.1.
††0.001<P≤0.01.