. Author manuscript; available in PMC: 2021 Jul 1.

Published in final edited form as: Obstet Gynecol. 2020 Jul;136(1):129–139. doi: 10.1097/AOG.0000000000003885

Table 1.

Characteristics of participants

Characteristic	Normal BP	Elevated BP	Stage 1 Hypertension	Stage 2 Hypertension	P value^*
N (%)	13640 (75.1)	2529 (13.9)	988 (5.4)	1005 (5.5)
Age (years)	29.7 ± 5.4	29.0 ± 5.7^†	30.2 ± 5.2^†	31.4 ± 5.3^†	<0.001
Pre-pregnancy BMI (kg/m²)	25.7 ± 5.6	30.7 ± 7.2^†	32.6 ± 7.8^†	35.1 ± 9.3^†	<0.001
Gestational weight gain category^‡		^†		^†	<0.001
Inadequate	2742 (21.5)	513 (21.6)	194 (21.0)	291 (31.7)
Adequate	3822 (30.0)	570 (24.0)	252 (27.3)	226 (24.6)
Excessive	6165 (48.4)	1289 (54.3)	477 (51.7)	401 (43.7)
Race		^†	^†	^†	<0.001
White	9588 (70.3)	1663 (65.8)	764 (77.3)	611 (60.8)
Black or African American	2565 (18.8)	729 (28.8)	176 (17.8)	362 (36.0)
Other/Not Specified	1487 (10.9)	137 (5.4)	48 (4.9)	32 (3.2)
Ethnicity					0.62
Hispanic or Latino	197 (1.4)	37 (1.5)	7 (0.7)	12 (1.2)
Not Hispanic or Latino	12297 (90.2)	2288 (90.5)	897 (90.8)	911 (90.6)
Declined/Not Specified	1146 (8.4)	204 (8.1)	84 (8.5)	82 (8.2)
Current smoker	1217 (9.5)	295 (12.4)^†	81 (8.8)	122 (13.1)^†	<0.001
Pre-existing diabetes	142 (1.0)	34 (1.3)	32 (3.2)^†	102 (10.1)^†	<0.001
First delivery	5971 (45.6)	1208 (49.8)^†	471 (49.6)^†	379 (39.7)^†	<0.001
Gestational age at first prenatal visit (weeks)	9.7 ± 2.5	9.5 ± 2.4^†	10.0 ± 2.5^†	9.2 ± 2.5^†	<0.001
Number of visits before 20 weeks of gestation	2.9 ± 0.9	3.0 ± 0.9^†	2.8 ± 0.8^†	3.3 ± 1.1^†	<0.001
Average SBP before 20 weeks of gestation (mmHg)	109.7 ± 6.2	123.1 ± 2.6^†	124.8 ± 6.9^†	128.3 ± 10.2^†	<0.001
Average DBP before 20 weeks of gestation (mmHg)	66.6 ± 5.9	70.8 ± 5.9^†	79.7 ± 5.0^†	77.1 ± 8.7^†	<0.001

Blood pressure group was assigned based on the highest eligible category for either average systolic or average diastolic blood pressure before 20 weeks of gestation; stage 2 hypertension includes women with diagnostic codes for chronic hypertension in addition to women who met blood pressure criteria.

BP, blood pressure; BMI, body mass index; SBP, systolic blood pressure; DBP, diastolic blood pressure

Data are n (%) or mean ± standard deviation

P values for continuous and categorical variables were generated from ANOVA F test and Pearson chi-square/Exact chi-square test, respectively.

^†

Pairwise comparison with normal BP group significant at p<0.05 level. For multi-category variables (race, gestational weight gain), p value presented is for overall test of differences between groups.

^‡

Gestational weight gain category was defined according to Institute of Medicine Criteria(31) Due to missing data (n=1220), subgroup totals do not add up to column total