Table 1. Frequency distribution of the variables .

Variable	Category	PCH1 group (n=100) N (%)	Healthy group (n=100) N (%)	p2
Positive history of cigarette smoking	-	23(23)	13(13)	0.097
Positive history of Alcohol consumption	-	7(7)	1(1)	0.065
Positive history of drugs abuse	-	4(4)	1(1)	0.369
Positive family history of CH	-	11(11)	2(2)	0.018
Mother's education	Under Diploma	24(24)	5(5)
	Diploma	45(45)	25(25)
	Associate and Bachelor	27(27)	57(57)	0.001
	Doctorate and Post-Doctorate	4(4)	13(13)
Mother's age at pregnancy (year)	20 ≥	5(5)	13(13)
	30-21	34(34)	69(69)	0.001
	31≤	61(61)	18(18)
Family income	Low3	8(8)	13(13)
	Medium4	50(50)	39(39)	0.229
	High5	48(48)	42(42)

¹Children with primary congenital hypothyroidism, ² p-values less than .05 were considered significant, ³ Family income less than 5000,000 Rials, ⁴ Family income 5000,000 to 10 million Rials, ⁵ Family income more than 10 million Rials