Endocrinol Metab.  2018 Sep;33(3):395-402. 10.3803/EnM.2018.33.3.395.

Effects of Maternal Iodine Status during Pregnancy and Lactation on Maternal Thyroid Function and Offspring Growth and Development: A Prospective Study Protocol for the Ideal Breast Milk Cohort

Affiliations
  • 1Department of Pediatrics, Seoul National University Children's Hospital, Seoul National University College of Medicine, Seoul, Korea.
  • 2Department of Internal Medicine, Seoul National University Hospital, Seoul National University College of Medicine, Seoul, Korea.
  • 3Department of Preventive Medicine, Seoul National University College of Medicine, Seoul, Korea.
  • 4Cancer Research Institute, Seoul National University College of Medicine, Seoul, Korea.
  • 5Department of Biomedical Science, Seoul National University Graduate School, Seoul, Korea.
  • 6Department of Obstetrics and Gynecology, Seoul National University Hospital, Seoul National University College of Medicine, Seoul, Korea. jhs0927@snu.ac.kr
  • 7Department of Food Service and Nutrition Care, Seoul National University Hospital, Seoul National University College of Medicine, Seoul, Korea.
  • 8Department of Laboratory Medicine, Seoul National University Hospital, Seoul National University College of Medicine, Seoul, Korea.
  • 9Department of Nuclear Medicine, Seoul National University Hospital, Seoul National University College of Medicine, Seoul, Korea. jkchung@snu.ac.kr

Abstract

BACKGROUND
Iodine is an intrinsic element of thyroid hormone, which is essential for childhood growth and development. The Ideal Breast Milk (IBM) cohort study aims to evaluate the effects of maternal iodine status during pregnancy and lactation on maternal thyroid function, offspring growth and development, and offspring thyroid function.
METHODS
The IBM cohort study recruited pregnant women from Seoul National University Hospital between June 2016 and August 2017, followed by enrollment of their offspring after delivery. For the maternal participants, iodine status is evaluated by urinary iodine concentration (UIC) and dietary records in the third trimester and at 3 to 4 weeks and 12 to 15 months postpartum. For the child participants, cord blood sampling and UIC measurements are performed at birth. At 3 to 4 weeks of age, UIC and breastmilk iodine concentrations are measured. At 12 to 15 months of age, growth and development are assessed and measurements of UIC, a thyroid function test, and ultrasonography are performed.
RESULTS
A total of 198 pregnant women in their third trimester were recruited. Their mean age was 35.1±3.5 years, and 78 (39.4%) of them were pregnant with twins. Thirty-three (16.7%) of them had a previous history of thyroid disease.
CONCLUSION
Korea is an iodine-replete area. In particular, lactating women in Korea are commonly exposed to excess iodine due to the traditional practice of consuming brown seaweed soup postpartum. The study of the IBM cohort is expected to contribute to developing guidelines for optimal iodine nutrition in pregnant or lactating women.

Keyword

Iodine intake; Pregnancy; Milk, human; Thyroid; Infant; Development

MeSH Terms

Breast*
Child
Cohort Studies*
Cordocentesis
Diet Records
Female
Growth and Development*
Humans
Infant
Iodine*
Korea
Lactation*
Milk, Human*
Parturition
Postpartum Period
Pregnancy Trimester, Third
Pregnancy*
Pregnant Women
Prospective Studies*
Seaweed
Seoul
Thyroid Diseases
Thyroid Function Tests
Thyroid Gland*
Twins
Ultrasonography
Iodine

Figure

  • Fig. 1 Study design.


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