TABLE 1.

Characteristics of supplement users and nonusers among pregnant women in NHANES 1999–2006

	Supplement users, n = 1007		Supplement nonusers, n = 289		Chi-square P value
	n	weighted % 1	n	weighted %
All pregnant women	1007	77.6 ± 2.2	289	22.4 ± 2.2	<0.0001
Age
<25 y	364	28.3 ± 2.7	181	56.7 ± 5.3	<0.0001
≥25 y	643	71.7 ± 2.7	108	43.2 ± 5.3
Race/ethnicity
Non-Hispanic white	508	62.5 ± 2.7	54	27.7 ± 5.7	<0.0001
Non-Hispanic black	129	12.3 ± 1.5	78	27.0 ± 4.6
Mexican-American	266	11.7 ± 1.4	125	23.6 ± 3.7
Other	104	13.5 ± 2.3	32	21.7 ± 6.4
Marital status
Unmarried	201	17.9 ± 2.5	126	46.5 ± 5.2	<0.0001
Married	772	76.0 ± 2.9	153	45.3 ± 4.7
Missing3	34	–	10	–
Parity
First birth	297	29.5 ± 2.7	58	17.0 ± 4.1	NS4
Second birth or higher	635	63.2 ± 3.3	193	69.5 ± 5.6
Missing	75	–	38	–
Trimester
First	141	16.3 ± 2.2	97	44.4 ± 6.1	<0.01
Second	372	34.7 ± 3.2	86	40.8 ± 5.3
Third	370	32.9 ± 3.1	50	14.8 ± 3.7
Missing	124	16.1 ± 2.6	56	25.7 ± 4.4
Health insurance
No	130	9.4 ± 1.4	110	34.8 ± 4.3	<0.0001
Yes	875	90.5 ± 1.4	173	63.8 ± 4.5
Missing	2	– 2	6	– 2
Poverty-income ratio
<1	286	15.2 ± 1.6	142	41.4 ± 6.7	<0.0001
1–1.9	202	16.5 ± 2.4	76	21.2 ± 4.9
≥2	519	59.4 ± 3.4	71	29.1 ± 5.9
Missing		70		25
Education
High school or less	480	33.9 ± 2.9	231	75.5 ± 4.5	<0.0001
Some college or more	526	66.0 ± 2.9	58	24.5 ± 4.5
Missing		1		0

¹Values are percentage ± SE based on weighted data.

²Denote unreliable estimates.

³Missing denotes women who were missing data for the variable of interest.

⁴P value ≥ 0.05.