Table 1.

Characteristics of study participants by gestational hypertension and preeclampsia: ollaborative Perinatal Project, 1959–66

Characteristic		Pregnancies n = 1,933	Gestational hypertension n = 6474				Preeclampsia n = 315
		No.	%	ORc	95% C.I.	%	ORc	95% C.I.
Age (year)	<=19	515	24.3	1.0	.	13.4	1.0	.
	20–29	1082	22.7	1.1	0.7 – 1.6	6.7	0.8	0.4 – 1.5
	>=30	336	36.4	1.8	1.1 – 3.1	11.0	1.0	0.4 – 2.4
Race	White	849	23.5	1.0	.	7.7	1.0	.
	Black	974	26.2	1.1	0.7 – 2.0	10.1	1.6	0.7 – 3.7
	Other	110	32.9	1.3	0.6 – 2.8	11.8	1.5	0.5 – 4.7
Previous pregnancies	None	664	28.6	1.0	.	15.2	1.0	.
	One or more	1269	23.8	0.6	0.4 – 0.9	6.3	0.3	0.2 – 0.6
Prepregnancy body mass index (kg/m2)	< 25	1543	22.8	1.0 6	.	8.1	1.0	.
	>=25	390	36.7	1.4	1.0 – 2.0	13.9	2.3	1.3 – 4.1
Socioeconomic indexa	<=5	1197	26.1	1.0	.	10.3	1.0	.
	> 5	736	24.1	1.0	0.7 – 1.5	7.3	0.7	0.4 –00201.5
Smoking status	Nonsmoker	770	26.7	1.0	.	9.4	1.0	.
	Past smoker	294	22.7	0.9	0.6 – 1.5	8.0	0.9	0.4 – 2.0
	Current smoker, <10/day	370	23.5	0.9	0.6 – 1.3	10.1	1.1	0.6 – 2.2
	Current smoker, 10–19/day	244	30.5	1.4	0.9 – 2.2	7.3	1.0	0.4 – 2.8
	Current smoker, >=20/day	255	22.3	0.8	0.5 – 1.3	9.8	1.2	0.6 – 2.5
Interpregnancy interval (year)b	< 2	913	23.6	1.0	.	5.2	1.0	.
	>=2	356	24.3	0.9	0.5 – 1.4	9.0	1.0	0.4 – 2.1

^aApproximately equal to percentile rank among contemporaneous U.S. households, divided by 10.

^bMost recent pregnancy, parous only (n = 1322, 87).

^cAdjusted for all covariates shown in table, study center and survey weight.