Lower educational status interferes with maternal iodine intake during both pregnancy and lactation

Abstract

Objective: To investigate factors affecting conscious iodine intake among pregnant and lactating women in a rural area in Hungary. Methods: Pregnant women were studied and followed during lactation. Urinary and breast milk iodine concentration (UIC and MIC) were measured by inductively coupled plasma mass spectrometry. Potential interfering factors, including age, educational status and smoking were assessed. Results: During pregnancy and lactation, mild iodine deficiency was obse rved; median UIC were 66 and 49 μg/L, respectively. Educational status was found to be a strong determinant of both iodine nutrition and smoking status during pregnancy (P < 0.01 and P < 0.001) and lactation (P < 0.001 and P < 0.01). While smoking and non-smoking lactating mothers had similar concentrations of urinary iodine (median UIC: 47 and 51 μg/L, P = 0.95), the breast milk of smoking mothers contained less iodin e (median MIC: 150 and 203 μg/L, P = 0.03). Conclusions: Both low iodine intake and smoking contribute to the higher risk of iodine deficiency in women with lower educational status. In smokers, M IC is often low in spite of normal UIC, presumably due to the iodine transport blocking effe ct of the cigarette smoke towards breast milk; normal UIC may be misinterpreted as sufficie nt iodine supply towards the child. Antenatal health promotion strategies should focus on young women with lower educational status, even in regions where sufficient iodine intak e has been achieved in non-pregnant adults.

Keywords

• iodine
• pregnancy
• lactation
• maternal education
• smoking