Table 2 Stratified comparisons of second and firstborn twins: rates and ORs of perinatal death
Variable | Twin births n(%) | Perinatal death n (per 1000) | ORa (95% CI) | Variance of random intercepts | |||
|---|---|---|---|---|---|---|---|
Firstborn | Secondborn | Laplace Fit | Bayesian Fitb | Laplace Fit | Bayesian Fit | ||
Birth weight, heavier in %c | |||||||
Heavier firstborn twin | |||||||
≥ 25% | 32,940 (8.74) | 358 (21.74) | 989 (60.05) | 4.15 (2.31, 6.13) | 3.42 (2.47, 4.70) | 104.2 | 3.5 |
15 to < 25% | 35,810 (9.50) | 295 (16.48) | 490 (27.37) | 2.31 (1.46, 3.65) | 1.97 (1.58, 2.49) | 74.7 | 5.5 |
5 to < 15% | 72,230 (19.16) | 565 (15.64) | 723 (20.02) | 1.68 (1.33, 2.12) | 1.39 (1.20, 1.62) | 42.3 | 4.4 |
Similar birth weight | |||||||
within ±5% | 109,998 (29.18) | 1040 (18.91) | 1174 (21.35) | 1.48 (1.28, 1.72) | 1.27 (1.13, 1.43) | 31.8 | 5.4 |
Heavier secondborn twin | |||||||
5 to < 15% | 69,804 (18.52) | 617 (17.68) | 608 (17.42) | 1.16 (0.90, 1.50) | 1.19 (0.97, 1.40) | 69.9 | 4.7 |
15 to < 25% | 32,118 (8.52) | 354 (22.04) | 334 (20.80) | 0.86 (0.67, 1.12) | 0.91 (0.71, 1.20) | 73.9 | 5.6 |
≥ 25% | 24,060 (6.38) | 506 (42.06) | 351 (29.18) | 0.14 (0.07, 0.26) | 0.33 (0.25, 0.45) | 107.5 | 3.3 |