Table 3.
Perinatal outcomes from twin pregnancies, Brazil, SINASC 2011-2014.
| Characteristics | Twin pregnancy n (%) | Single pregnancy n (%) | PR (95%CI) | |||
|---|---|---|---|---|---|---|
| Gestational age at birth a | ||||||
| < 32 weeks | 12 835 (10.19) | 147 877 (1.35) | 12.13 (11.93 – 12.33) | |||
| 32-36 weeks | 54 644 (43.38) | 1 011 082 (9.21) | 5.17 (5.14 – 5.20) | |||
| ≥ 37 weeks | 58 478 (46.43) | 9 820 746 (89.44) | Ref. | |||
| Onset of labor b | ||||||
| Spontaneous | 34 788 (40.39) | 1 321 135 (29.97) | Ref. | |||
| Induced | 9 396 (11.02) | 1 425 306 (32.34) | 0.25 (0.24 – 0.26) | |||
| No labor | 41 103 (48.19) | 1 661 230 (37.69) | 0.94 (0.93 – 0.95) | |||
| Type of birth c | ||||||
| Vaginal | 24 774 (19.09) | 5 092 746 (44.64) | Ref. | |||
| Cesarean section | 105 014 (80.91) | 6 314 703 (55.36) | 3.38 (3.33 – 3.42) | |||
|
| ||||||
| PR (95%CI) | ||||||
| 1st twin n (%) | 2nd twin n (%) | N (%) | 1st vs single | 2nd vs single | 2nd vs 1st | |
|
| ||||||
| Birthweight d | ||||||
| < 2500g | 75 730 (58.28) | 63 213 (61.19) | 831 068 (7.28) | 17.8 (17.6-18.0) | 20.1 (19.8-20.3) | 1.1 (1.1-1.1) |
| ≥ 2500g | 54 213 (41.72) | 40 088 (38.81) | 10 582 757 (92.72) | Ref. | Ref. | Ref. |
| Presentation e | ||||||
| Cephalic | 84 095 (77.04) | 61 834 (72.14) | 6 692 704 (96.32) | Ref. | Ref. | Ref. |
| Non-cephalic | 25 067 (22.96) | 23 883 (27.86) | 255 596 (3.68) | 7.8 (7.7-7.9) | 10.1 (9.9-10.3) | 1.3 (1.3-1.3) |
| Congenital malformation f | ||||||
| Yes | 1 470 (1.16) | 1 144 (1.14) | 87 586 (0.79) | 1.5 (1.4-1.6) | 1.4 (1.3-1.5) | 1.0 (0.9-1.1) |
| Not | 124 846 (98.84) | 99 406 (98.86) | 11 002 510 (99.21) | Ref. | Ref. | Ref. |
| 5 th min Apgar g | ||||||
| < 7 | 3 808 (3.00) | 2 787 (2.76) | 115 749 (1.05) | 2.9 (2.8-3.0) | 2.7 (2.6-2.8) | 1.1 (1.0-1.1) |
| ≥ 7 | 122 942 (97.00) | 98 283 (97.24) | 10 959 760 (98.95) | Ref. | Ref. | Ref. |
Missing data: (a) 446 045. (b) 7 058 749. (c) 14 470. (d)9 565. (e) 4 513 455. (f) 3 396 672. (g) 353 305.