TABLE 1

Baseline Characteristics and Hospitalization Rates According to GA Group

CharacteristicEPI (n = 184 589)LPI (n = 517 879)TI (n = 5 943 809)P
GA, median (IQR), wk32 (29–33)36 (35–36)39 (38–40)<.001
Birth weight, median (IQR), g2041 (1475–2880)2845 (2495–3275)3425 (3120–3742)<.001
Female infant85 552 (46.4)242 016 (46.7)2 920 133 (49.1)<.001
Small for GA15 650 (8.5)54 614 (10.6)505 243 (8.5)<.001
Adolescent mother25 614 (13.9)63 222 (12.2)630 740 (10.6)<.001
Nonprimiparous mother116 589 (63.2)329 040 (63.5)3 626 962 (61.0)<.001
Multiple gestation33 893 (18.4)60 974 (11.8)81 586 (1.4)<.001
Trimester of prenatal care initiation<.001
 First142 684 (77.3)415 814 (80.3)4 953 560 (83.3)
 Second31 867 (17.3)76 494 (14.8)765 331 (12.9)
 Third10 038 (5.4)25 571 (4.9)224 918 (3.8)
Maternal education<.001
 Less than high school63 702 (34.5)173 733 (33.6)1 808 018 (30.4)
 High school graduate87 899 (47.6)242 245 (46.8)2 815 116 (47.4)
 ≥1 year of college32 988 (17.9)101 901 (19.7)1 320 675 (22.2)
Maternal race<.001
 Hispanic82 428 (44.7)233 958 (45.2)2 647 640 (44.5)
 White59 757 (32.4)175 749 (33.9)2 191 281 (36.9)
 Black21 125 (11.4)43 028 (8.3)337 582 (5.7)
 Asian14 318 (7.8)46 961 (9.1)563 574 (9.5)
 Other6961 (3.8)18 183 (3.5)203 732 (3.4)
Health insurance<.001
 Private83 838 (45.4)250 943 (48.5)3 147 827 (53.0)
 Federal93 700 (50.8)249 373 (48.2)2 613 855 (44.0)
 Uninsured7051 (3.8)17 563 (3.4)182 127 (3.1)
Birth hospitalization length, median (IQR), days13 (2–35)2 (1–4)2 (1–2)<.001
Any hospitalization within 14 days of birth discharge6787 (3.7)18 545 (3.6)132 383 (2.2)<.001
Any hospitalization within 30 days of birth discharge11 026 (6.0)25 986 (5.0)200 503 (3.4)<.001
Any hospitalization within 90 days of birth discharge19 508 (10.6)42 411 (8.2)344 197 (5.8)<.001
Any hospitalization between birth discharge and  day 365 of life29 590 (16.0)64 657 (12.5)565 699 (9.5)<.001
  • Values are presented as n (%) unless otherwise noted. Percentages may sum to >100% due to rounding. IQR, interquartile range.