TABLE 1

Infant and Maternal Characteristics by Dissimilarity Quartile

First Quartile: Lowest QuartileSecond QuartileThird QuartileFourth Quartile: Highest QuartileP
n (N = 70 775)17 77617 67117 74417 584
Dissimilarity range0.055–0.2360.236–0.3920.392–0.6640.664–0.822
Race, %<.001
 Black18.321.540.364.4
 White81.778.559.735.6
State, %<.001
 California89.879.184.236.2
 Missouri10.29.36.029.4
 Pennsylvania0.0111.69.934.5
Mean maternal age, y29.128.328.327.6<.001
Mean BW, g1748173217361533<.001
Chorioamnionitis, %15.316.115.820.9<.001
Pregnancy-induced hypertension, %14.914.714.716.6<.001
Chronic hypertension, %2.02.02.32.5.010
Preterm labor, %71.371.569.572.7<.001
Mean poverty rate in maternal ZC, %9.713.517.522.7<.001
Mean median income in maternal ZC, $55 60145 28043 31333 480<.001
Mean high school attendance rate in maternal ZC, %82.376.175.269.9<.001
Mean college attendance rate in maternal ZC, %26.222.125.019.9<.001
Mean home value in maternal ZC, $206 298179 489184 326127 767<.001
Mean rent rate in maternal ZC, $33.041.346.748.6<.001
IVH cases, n (%)1846 (10.4)1922 (10.9)2031 (11.5)2259 (12.9)<.001
  • —, not applicable.