Effects of mandatory salt iodization on breast milk, urinary iodine concentrations, and thyroid hormones: is iodine deficiency still a continuing problem?
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To investigate whether mandatory use of iodized salt in Turkey, since 1999 has sufficient effects on pregnant women and their newborns’ urinary iodine concentrations (UIC), maternal and newborns’ thyroid function tests and breast milk iodine concentrations (BMIC).
This cross-sectional analytical-type study was conducted in an obstetrics and gynecology hospital in Konya, Turkey. One hundred and seven pregnant women and their 107 full-term newborns were included into the study. Levels of pregnant women and their newborns’ UIC, thyroid-stimulated hormone (TSH), free triiodothyronine (fT3), free thyroxine (fT4), thyroglobulin (Tg), and BMIC were studied.
Of 107 women with term pregnancy, mean TSH value and hypothyroidism frequency were found as 2.34 ± 1.33 mIU/L and 18.7%, respectively. Cord blood TSH level was found higher (≥ 10 mIU/L) in five newborns. Accordingly, the incidence of transient congenital hypothyroidism was 4.7% (5/107). Tg levels were observed to be higher in 50.5% of newborns and 22.4% of pregnant women. Frequency of iodized salt use in pregnancies was detected as 96.3% in general population, 97.5% in urban, and 92.9% in rural areas. Of pregnancies and newborns, 57.9 and 53.3% were found to have deficient urinary iodine, respectively, and BMIC deficiency was detected as 52.0%. There was a significant positive correlation between pregnant women’s UIC, and newborns’ UIC and BMIC.
Despite the effective struggle with iodine deficiency and salt iodination control program in Konya, we concluded that iodine deficiency still persists as a significant problem in pregnancies.
KeywordsBreast milk iodine concentration Urinary iodine concentration Newborn Pregnant Thyroid hormones
We wish to thank the Necmettin Erbakan University Scientific Research Coordination Center (BAP) for the financial support to this study. We also thank to the mothers and their infants for their participation in this study.
Compliance with ethical standards
Conflict of interest
The authors declare that they have no conflicts of interest.
This study was planned according to the Helsinki Declaration and was approved by the Ethics Board of Necmettin Erbakan University (approval number: 2013/29).
All pregnant women were informed about the study design, and oral and written informed consent was obtained from all individual participants included in the study.
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