Table 2.

Prevalence of dietary supplement use by trimester of pregnancy among pregnant women (20-44y) in the United States, NHANES 1999-2012 (n=790)

	Trimester*
	First (n=147)	Second (n=332)	Third (n=311)
Any supplement use	72.0 ± 5.8 a	86.3 ± 2.5 a,b	90.8 ± 2.4 b
Multi-vitamin-mineral	69.9 ± 5.8 a	82.2 ± 3.0 a	87.0 ± 3.1 a
Folic acid-containing	70.6 ± 5.9 a	84.3 ± 2.9 a	87.5 ± 3.0 a
Iron-containing	66.1 ± 6.2 a	81.9 ± 3.0 a,b	89.3 ± 2.5 b
Iodine-containing	22.8 ± 5.9 a	19.8 ± 3.5 a	22.8 ± 4.2 a
Prenatal supplement use	52.4 ± 6.3 a	80.0 ± 3.1 b	80.4 ± 3.4 b

NHANES, National Health and Nutrition Examination Survey

All estimates are percentages ± SEs.

Estimates with different alphabetic characters are significantly different from each other at P<0.0167.

^*Information on month of pregnancy was only available in 1999-2012. The 461 women who did not have information on month of pregnancy are not included.