Table 1.

Demographic characteristics by racial group

	All N=510 288 %	NHW N=326 761 %	NHB N=122 351 %	Hispanic N=61 176 %
Maternal age (years)
15–19	12.69	9.36	19.94	16.02
20–24	28.26	23.82	35.41	37.67
25–29	27.04	28.40	22.95	27.91
30–34	21.67	25.98	14.17	13.64
35–39	8.88	10.72	6.34	4.10
40–44	1.47	1.72	1.20	0.66
Maternal education (completed)
Middle school	5.97	1.68	1.60	37.59
Some high school	16.03	12.02	21.60	26.26
High school	30.58	28.84	39.32	22.38
Some college	23.39	24.40	24.05	8.38
College	25.03	33.05	13.43	5.39
Unmarried	33.91	19.52	66.21	46.17
Birth order
First	43.33	44.95	40.33	40.66
Second	35.07	35.99	33.54	33.18
Third	16.10	14.74	18.62	18.36
Fourth	5.50	4.31	7.50	7.80
Infant sex male	51.07	51.23	50.64	51.10
Gestational age in weeks (mean, SD)	38.82 (1.83)	38.86 (1.75)	38.59 (2.07)	39.03 (1.71)
Birthweight in grams (mean, SD)	3343.63 (557.97)	3409.15 (547.47)	3166.25 (568.67)	3348.39 (513.20)

All values are expressed as percentages unless otherwise specified.

NHB, non-Hispanic black; NHW, non-Hispanic white.