Table 1.

Descriptive statistics and bivariate chi-square tests between explanatory covariates and maternal race and infant mortality among live, singleton births to Black and non-Hispanic White mothers in Michigan, 1989–2005.

	Overall	Non-Hispanic White	African–American	p-values
	(n = 2,087,191)	(n = 1,666,555)	(n = 420,636)
	%	%	%
Infant mortality rate (per 1000 live births)	7.6	5.6	15.5	<0.001
Preterm birth				<0.001
Yes	7.9	6.6	13.1
No	92.1	93.4	86.9
Prenatal care*				<0.001
Adequate	76.1	80.5	58.6
Inadequate	24.0	19.6	41.4
Parity				<0.001
0 previous	31.6	32.6	27.4
1 previous	28.8	30.1	23.6
2+	39.7	37.3	49.1
Marital status				<0.001
Unmarried	32.6	22.0	74.5
Married	67.5	78.0	25.5
Maternal age				<0.001
<20	11.7	8.9	22.7
20–35	80.4	82.6	71.6
36+	8.0	8.6	5.7
Education				<0.001
<12 years	17.2	13.5	32.0
12 years	36.2	35.8	37.8
>12 years	46.6	50.7	30.2
Payment source				<0.001
Private insurance	66.7	72.8	42.8
Medicaid, self-pay, other	33.3	27.2	57.2
Mother US born				<0.001
Yes	95.6	95.0	98.2
No	4.4	5.0	1.8
Alcohol use				<0.001
None	98.3	98.4	97.7
Yes	1.7	1.6	2.3
Smoking				<0.001
None	81.3	80.7	83.4
Yes	18.8	19.3	16.6

^*The Kessner/Institute of Medicine Adequacy of Prenatal Care Index (Kessner et al., 1973) was calculated and analyzed as a binary variable denoting adequate vs. inadequate prenatal care.