Table 4 Race-stratified Analysis of Mortality and Morbidity in Male and Female Co-twins in Mixed-Gender Twin Pairs.

From: Gender Differences in Infant Mortality and Neonatal Morbidity in Mixed-Gender Twins

Race Outcomes The male twins (n, %) The female twins (n, %) OR (95%CI) aOR (95%CI)
White Fetal mortality 725 (0.86) 716 (0.85) 1.02 (0.89, 1.17) NA
Congenital abnormality 1460 (1.75) 1180 (1.41) 1.36 (1.24, 1.49) NA
Infant mortality 1638 (1.97) 1457 (1.76) 1.35 (1.21, 1.50) 1.51 (1.34, 1.70)
 Neonatal mortality 1351 (1.63) 1217 (1.47) 1.39 (1.21, 1.59) 1.58 (1.36, 1.83)
Low 5-minute Apgar score (<7) 2336 (2.82) 2175 (2.62) 1.14 (1.05, 1.23) 1.17 (1.08, 1.28)
Assistant ventilation >30 minutes 3390 (4.09) 2997 (3.61) 1.51 (1.38, 1.65) 1.42 (1.28, 1.57)
Respiratory distress syndrome 2464 (5.6) 2158 (4.90) 1.63 (1.45, 1.82) 1.51 (1.34, 1.71)
Black Fetal mortality 374 (1.83) 376 (1.84) 0.99 (0.80, 1.22) NA
Congenital abnormality 340 (1.70) 283 (1.41) 1.34 (1.09, 1.66) NA
Infant mortality 974 (4.90) 898 (4.51) 1.22 (1.05, 1.41) 1.37 (1.17, 1.62)
Neonatal mortality 754 (3.79) 703 (3.53) 1.27 (1.04, 1.56) 1.58 (1.25, 2.01)
Low 5-minute Apgar score (<7) 1193 (6.00) 1183 (5.94) 1.05 (0.93, 1.17) 1.13 (0.99, 1.30)
Assistant ventilation >30 minutes 818 (4.11) 799 (4.01) 1.06 (0.86, 1.30) 1.09 (0.85, 1.30)
Respiratory distress syndrome 513 (4.35) 493 (4.18) 1.13 (0.88, 1.46) 1.09 (0.83, 1.44)
Others Fetal mortality 35 (1.02) 34 (0.99) 1.06 (0.55, 2.05) NA
Congenital abnormality 67 (1.97) 44 (1.29) 2.18 (1.32, 3.61) NA
Infant mortality 63 (1.86) 57 (1.68) 1.24 (0.73, 2.10) 1.39 (0.77, 2.49)
Neonatal mortality 47 (1.39) 44 (1.30) 1.23 (0.59, 2.56) 1.60 (0.62, 4.15)
Low 5-minute Apgar score (<7) 83 (2.45) 73 (2.07) 1.49 (0.96, 2.31) 1.56 (0.97, 2.49)
Assistant ventilation >30 minutes 110 (3.25) 101 (2.98) 1.31 (0.81, 2.13) 1.26 (0.76, 2.10)
Respiratory distress syndrome 69 (4.10) 70 (4.16) 0.93 (0.45, 1.93) 1.01 (0.54, 2.30)
  1. OR: Odds Ratio; aOR: Odds Ratio adjusted by birth weight, birth order and methods of delivery.