Iodised salt and iodine levels in pregnant women and newborns
What it found
In 107 pregnant women and their newborns in Turkey, over half had low iodine in their urine and about half of the breast milk samples were low in iodine, even though almost all the women used iodised salt.
What they found
Studies in people
Iodised salt use
Almost all the pregnant women used iodised salt: 96.3% overall, 97.5% in cities and 92.9% in rural areas.
Low iodine in urine
Low iodine in urine was found in 57.9% of the pregnant women and 53.3% of the newborns.
Low iodine in breast milk
Breast milk iodine was low in 52.0% of the samples.
Thyroid hormone levels
The women's average thyroid-stimulating hormone was 2.34 mIU/L, and 18.7% of them had an underactive thyroid. Cord blood thyroid-stimulating hormone was high (10 mIU/L or more) in five newborns, giving a rate of transient congenital hypothyroidism of 4.7%.
Thyroglobulin levels
Thyroglobulin was higher than normal in 50.5% of newborns and 22.4% of pregnant women.
Link between mother and baby
The mothers' urinary iodine was linked to the babies' urinary iodine and to the iodine in breast milk.
What the authors conclude
“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.”
Also in their conclusions
- They concluded that iodine deficiency still persists as a significant problem in pregnancies in Konya, despite the effective struggle with iodine deficiency and the salt iodination control program.
How it was done
Turkey has required iodised salt since 1999. The authors wanted to check whether that requirement is enough to protect pregnant women and their newborns from iodine deficiency.
They studied 107 pregnant women and their 107 full-term newborns at an obstetrics and gynecology hospital in Konya, Turkey. They measured iodine in the women's and babies' urine, thyroid hormones in both, and iodine in breast milk.
What it can’t tell you
- We summarised it from the abstract only.
- This study looked at one group of women at one point in time, so it cannot prove that iodised salt caused the iodine levels seen.
- It was done in one city in Turkey, so the results may not apply to other places or other groups of people.
Who paid
- Authors work at
- Güzelyurt District Government Hospital, Turkey; University of Necmettin Erbakan, Turkey; Karatay Fetih Family Health Center, Turkey
The paper
- Title
- Effects of mandatory salt iodization on breast milk, urinary iodine concentrations, and thyroid hormones: is iodine deficiency still a continuing problem?
- Type
- Study
- Evidence
- Studies in people
- Summarised from
- Abstract only
- Cite
- Isiklar Ozberk D, Kutlu R, Kilinc I, Kilicaslan AO (2019). Effects of mandatory salt iodization on breast milk, urinary iodine concentrations, and thyroid hormones: is iodine deficiency still a continuing problem?. Journal of endocrinological investigation. doi:10.1007/s40618-018-0930-0PubMed 30099723DOI
Summary written 26 Sep 2026. Check it against the paper before it changes what you eat. How we summarise papers · Report an error