Table 1.

Classification of prenatal vitamins and recommended dosage.

Brands	A	B	C	D	E	F
Processing Sources	Natural and synthetic	Synthetic	Organic	Natural and synthetic	Natural	Natural and synthetic
Recommended dose (tablets/day)	4	1	4	1	3	3

A total of eight prenatal vitamins from six different brands were purchased from retailers. Three bottles of prenatal vitamins of brand F were purchased from different retailers. According to the process source, these vitamins were classified into three categories, natural/organic, synthetic, and a combination of natural and synthetic.