Table 1.

Social characteristics of the groups studied.

Social variable	Nonpregnant women	Pregnant women
Age (years)	29.250 ± 2.314	28.333 ± 1.971
Ethnicity	Han	Han
Occupation
Housewife	0	3
Employee	20	27
Level of education
<Technical	6	10
Bachelor	9	13
Master	5	7
Economic status	Regular	Regular