Research Article

Twin Pregnancy in Brazil: A Profile Analysis Exploring Population Information from the National Birth E-Registry on Live Births

Table 3

Perinatal outcomes from twin pregnancies, Brazil, SINASC 2011-2014.

CharacteristicsTwin pregnancy n (%)Single pregnancy n (%)PR (95%CI)

Gestational age at birth
 < 32 weeks12 835 (10.19)147 877 (1.35)12.13 (11.93 – 12.33)
 32-36 weeks54 644 (43.38)1 011 082 (9.21)5.17 (5.14 – 5.20)
 ≥ 37 weeks58 478 (46.43)9 820 746 (89.44)Ref.
Onset of labor
 Spontaneous34 788 (40.39)1 321 135 (29.97)Ref.
 Induced9 396 (11.02)1 425 306 (32.34)0.25 (0.24 – 0.26)
 No labor41 103 (48.19)1 661 230 (37.69)0.94 (0.93 – 0.95)
Type of birth
 Vaginal24 774 (19.09)5 092 746 (44.64)Ref.
 Cesarean section105 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 single2nd vs single2nd vs 1st

Birthweight
 < 2500g75 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)
 ≥ 2500g54 213 (41.72)40 088 (38.81)10 582 757 (92.72)Ref.Ref.Ref.
Presentation
 Cephalic84 095 (77.04)61 834 (72.14)6 692 704 (96.32)Ref.Ref.Ref.
 Non-cephalic25 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
 Yes1 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)
 Not124 846 (98.84)99 406 (98.86)11 002 510 (99.21)Ref.Ref.Ref.
5th min Apgar
 < 73 808 (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)
 ≥ 7122 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.