A population-based study of race-specific risk for placental abruption

Table 2 Baseline characteristics by race in cases of placental abruption (n = 5,065)

Characteristics	Black	White
	n (%)	n (%)	P*
Number of births with abruption	1,108	3,957
Rate of abruption for births to	1.0%	0.7%	< 0.001
Black and White mothers
Mean gestational age at delivery	34.0 ± 5.4	35.7 ± 4.6	< 0.001
Maternal age (years)	25.1 ± 6.3	27.0 ± 6.0	< 0.001
Maternal age categories			< 0.001
Age < 20 years	235 (21.2)	472 (11.9)
Age ≥ 20 and < 35 years	769 (69.4)	3,028 (76.5)
Age ≥ 35 years	104 (9.4)	457 (11.6)
Maternal education < 12 years	381 (35.4)	804 (20.5)	< 0.001
Indicators of low socioeconomic status†	887 (80.8)	1,678 (42.5)	< 0.001
Unmarried	879 (79.4)	1,070 (27.1)	< 0.001
Primigravida	307 (27.9)	1,444 (36.6)	< 0.001
No prenatal care	143 (13.8)	68 (1.8)	< 0.001
Body mass index categories			< 0.001
Body mass index < 20	217 (21.0)	1,061 (27.9)
Body mass index ≥ 20 and ≤ 30	675 (65.2)	2,322 (61.1)
Body mass index > 30	144 (13.9)	415 (10.9)
Type I or II Diabetes	23 (2.1)	94 (2.4)	0.607
Chronic hypertension	29 (2.6)	52 (1.3)	0.001
Gestational hypertension	107 (9.7)	316 (8.0)	0.074
Renal disease	4 (0.4)	21 (0.5)	0.562
Alcohol use	83 (7.6)	118 (3.0)	< 0.001
Cigarette use	307 (28.0)	1,364 (34.7)	0.008

* The p value for a chi-square test, adjusted for clustering for more than one birth to one mother.
† The composite indicator of low socioeconomic status, which includes Medicaid, WIC or food stamps.
Some percentages do not add up due to missing values (less than 5% for any given variable).

ISSN: 1471-2393