Table 3.

Education level and iodine nutrition during pregnancy and lactation.

	Education		P valuea
	≤ 8 years, n = 55	> 8 years, n = 40
Age (years), median (IQR)	21 (18–27)	27 (25–30)	<0.001
Awareness about iodine, %	62	88	<0.01
Nullparity, %	33	55	0.03
Previous miscarriage, %	20	15	0.530
Pregnancy
Gestational weeks, median (IQR)	18 (15–26)	20 (15–28)	0.718
Use of iodised salt, %	35	73	<0.001
Use of pregnancy supplements, %	71	98	<0.001
Use of iodine-containing supplements, %	55	53	0.844
Smoking, %	38	8	<0.001
UIC (µg/L), median (IQR)	47 (30–84)	87 (43–150)	<0.01
UIC (µg/g creatinine), median (IQR)	50 (35–68)	104 (45–157)	<0.001
Preterm birth (<37 weeks), %	11	13	0.811
Lactation
Weeks after delivery, median (IQR)	8 (6–9)	7 (6–8)	0.658
Use of iodised salt, %	20	84	<0.001
Use of pregnancy supplements, %	14	64	<0.001
Use of iodine-containing supplements, %	6	35	<0.001
Smoking, %	36	10	<0.01
UIC (µg/L), median (IQR)	47 (32–66)	61 (36–90)	0.100
UIC (µg/g creatinine), median (IQR)	45 (35–66)	82 (52–111)	<0.005
MIC (µg/L),b median (IQR)	171 (99–227)	241 (199–311)	<0.001

^afor continuous variables Mann–Whitney U test, for binary variables chi-square test and, in case of groups n < 10, Fisher’s exact test were used; ^bn = 93.

IQR, interquartile range; MIC, milk iodine concentration; UIC, urinary iodine concentration.