Table 1.

Demographic characteristics of clinically diagnosed placental abruption cases and controls

Maternal characteristics	Abruption cases (n=162)		Controls (n=173)
	n	%	n	%
Maternal age (years)
<20	8	4.9	11	6.4
20–24	27	16.7	23	13.3
25–29	36	22.2	36	20.8
30–34	49	30.3	55	31.8
≥35	42	25.9	48	27.7
Parity
Parity 0	54	33.3	61	35.3
Parity 1	59	36.4	61	35.3
Parity ≥2	49	30.3	51	29.5
Gestational age (weeks)
<25	12	7.4	2	1.2
25–35	94	58.0	19	11.0
≥37	56	34.6	152	87.9
Maternal race/ethnicity
Caucasian	56	34.6	67	38.7
Hispanic	55	34.0	53	30.6
African American	26	16.1	28	16.2
Other	25	15.4	25	14.5
Maternal education (years)
<9	14	8.6	15	8.7
9–12	62	38.3	48	27.7
13–15	67	41.4	75	43.4
≥16	20	12.4	35	20.2
Prepregnancy BMI
Underweight	35	21.6	32	18.5
Normal	75	46.3	81	46.8
Overweight	32	19.8	33	19.1
Obese	20	12.4	27	15.6
Maternal smoking	23	14.2	18	10.4
Alcohol use	1	0.6	8	4.6
Preeclampsia	23	14.2	2	1.2

BMI, body-mass index

Alcohol use = 1–7 drinks per week