Table 4.
Pregnancy outcomes of triplets reduced to twins versus primary twins.
| Primary twins(n=2788) | Triplets reduced to twins(n=331) | Unadjusted P Value | Unadjusted OR (95% CI) | Adjusted P Value | Adjusted OR (95% CI) | |
|---|---|---|---|---|---|---|
| GA at delivery | 37.00 (35.71-38.00) | 37.00 (35.71-37.86) | 0.992 | – | 0.957 | – |
| Delivery<32weeks | 126 (4.5) | 17 (5.1) | 0.612 | 1.14 (0.68-1.92) | 0.590 | 1.04 (0.91-1.19) |
| Delivery<34weeks | 281 (10.1) | 38 (11.5) | 0.426 | 1.16 (0.81-1.66) | 0.284 | 1.05 (0.96-1.15) |
| Delivery<37weeks | 1240 (44.5) | 150 (45.3) | 0.771 | 1.04 (0.82-1.30) | 0.764 | 1.01 (0.95-1.07) |
| Pregnancy loss <24weeks | 182 (6.5) | 22 (6.6) | 0.934 | 1.02 (0.65-1.61) | 0.877 | 1.01 (0.90-1.14) |
| Abortion of one fetus | 392 (14.1) | 46 (13.9) | 0.936 | 0.99 (0.71-1.37) | 0.549 | 0.98 (0.90-1.06) |
| All surviving | 2188(78.5) | 263(79.5) | 0.682 | 1.06 (0.80-1.41) | 0.397 | 1.03(0.96-1.11) |
| Caesarean section | 2401/2591 (92.7) | 290/309 (93.9) | 0.447 | 1.21 (0.74-1.97) | 0.371 | 1.06 (0.94-1.20) |
| Birth weight (g) | 2550 (2225-2850) | 2500 (2200-2800) | 0.130 | – | 0.195 | – |
| At least one LBW | 1311 (47.0) | 176 (53.2) | 0.034 | 1.28 (1.02-1.61) | 0.028 | 1.07 (1.01-1.13) |
| At least one VLBW | 106 (3.8) | 11 (3.3) | 0.665 | 0.87 (0.46-1.64) | 0.708 | 0.97 (0.83-1.14) |
| At least one SGA | 1103 (39.6) | 148 (44.7) | 0.071 | 1.24 (0.98-1.55) | 0.040 | 1.06 (1.00-1.13) |
Data are presented as median (IQR) or number (%). Mann–Whitney U tests and Chi-square tests or Fisher’s exact test were used for unadjusted analysis. Logistic regression and linear regression were used for adjusting certain confounders, including maternal age at conception, maternal BMI before pregnancy, type of infertility, ART methods, embryo transplantation, source of semen.
Birth weight, at least one LBW, and at least one VLBW were additionally adjusted for GA at delivery.
GA, gestational age; LBW, low birth weight; VLBW, very low birth weight; SGA, small for gestational age; OR, odds ratio; CI, confidence interval.