TABLE 1.

Characteristics of Live Births ≥500 g Birth Weight and 23 to 26 Weeks’ Gestation

CohortNew JerseyThe NetherlandsP
Birth year1984–19871983
Live births146142
Gestational age* (wk)25.0 ± 0.125.4 ± 0.1<.001
Birth weight* (g)
 23 wk617 ± 14693 ± 83
 24 wk711 ± 23663 ± 24.013
 25 wk776 ± 21839 ± 14
 26 wk910 ± 21956 ± 17
SGA21 (14%)10 (7%).04
Maternal age* (y)26.4 ± 0.626.7 ± 0.4.66
PIH/preeclampsia9 (6%)3 (2%).08
ROM >24 h41 (31%)33 (23%).17
Chorioamnionitis12 (8%)14 (10%).63
Male:female1:0.91:0.9.80
Race
 White89 (61%)119 (91%)
 Black43 (29%)6 (4%)<.001
 Other14 (10%)17 (12%)
Apgar score
 1 min3 (1–5)4 (2–6).04
 5 min6 (4–7)6 (2–8).88
  • SGA indicates small for gestational age; PIH, pregnancy-induced hypertension; ROM, rupture of membranes.

  • * Mean ± SEM.

  • Median (lower and upper quartiles).