TABLE 2

Infant Characteristics

NAS (n = 3842)No-NAS (n = 1 018 421)OR (95% CI)P
Male gender2017 (52.5)523 676 (51.4)1.04 (0.98–1.11).18
Rural residence at birth684 (17.8)191 720 (18.8)0.93 (0.86–1.02).11
Mean birth weight, g2868 ± 5933386 ± 569<.001
Low birth weight (<2500 g)961 (25.0)58 825 (5.8)5.44 (5.06–5.86)<.001
Mean gestational age, wk37.9 ± 2.539.0 ± 1.9<.001
Preterm birth (<37 wk gestation)860 (22.4)68 165 (6.7)4.02 (3.73–4.34)<.001
Multiple birtha74 (1.9)30 640 (3.0)0.63 (0.50–0.80)<.001
Resuscitation at birth1658 (43.2)388 383 (38.1)1.23 (1.16–1.31)<.001
Apgar <7 at 5 min139 (3.7)13 790 (1.4)2.77 (2.33–3.28)<.001
Admission to nursery2866 (74.6)161 079 (15.8)15.63 (14.53–16.81)<.001
Admission to an NICU270 (7.0)23958 (2.4)3.14 (2.77–3.55)<.001
Admission for birth defect3 (0.1)1359 (0.1).35
Birth in nontertiary obstetric hospitalb1899 (49.4)492 412 (63.6)0.56 (0.53–0.60)<.001
Transferred after birthc169 (4.4)29 586 (2.9)1.54 (1.32–1.80)<.001
Died before discharge from birth hospital5 (0.1)1856 (0.2)0.71 (0.30–1.72).45
Median length of stay after birth, d10.03.0<.001
  • Data expressed as number (%) or mean ± SD unless otherwise stated. —, analysis not applicable, not conducted, or data not available.

  • a Number of individual infants born as part of twin, triplet, or quadruplet birth.

  • b Nontertiary hospital defined as hospital obstetric level 1–5.35 Private hospital births not included in this comparison.

  • c Transferred refers to infants transferred to another hospital after birth.