Newswise — There is no correlation between newborn thyroid function within the normal range and cognitive development, nor is there a correlative between maternal thyroid function and newborn thyroid function in a Boston-area sample, according to data to be presented on Oct. 4, 2008 at the 79th Annual Meeting of the American Thyroid Association (ATA) in Chicago, IL. Normal thyroid function is essential for healthy brain development. Previous studies have suggested that even mild maternal hypothyroidism during pregnancy may adversely affect child cognitive development.
On behalf of Project Viva, a team of researchers led by Dr. Emily Oken of Harvard Medical School and Harvard Pilgrim Health Care and Dr. Elizabeth Pearce of Boston University Medical Center in Boston, Mass., studied 500 children born 1999-2003 to evaluate the relationship between thyroxine levels in newborns, first trimester maternal thyroid function, and childhood cognition. Researchers first tested mothers' thyroid stimulating hormone, thyroxine, and thyroid peroxidase (TPO) antibody levels at an average of 10.2 weeks gestation and later measured newborns' thyroxine levels from whole blood samples after birth.
Researchers then performed cognitive testing when the infants were six months old using the visual recognition memory (VRM) test, a measure of infant cognition that can predict later childhood IQ and specific abilities in perceptual speed, language, and memory. When the children were three years old, researchers tested them with the Peabody Picture Vocabulary Test (PPVT), a measure of verbal ability or scholastic aptitude, and the Wide Range Assessment of Visual Motor Ability (WRAVMA), which evaluates visual-spatial analysis, visual-motor ability, and fine motor skills.
Researchers found no correlation between newborn thyroxine levels and maternal thyroxine, TSH or TPO antibody levels. After performing multivariable linear regression analysis, researchers found higher thyroxine was associated with slightly poorer scores on the VRM among infants at six months, but not with scores at age three on either the PPVT or the WRAVMA; maternal thyroid function was not found to be related to child cognitive test scores.
"In this sample from an iodine sufficient area, first-trimester maternal thyroid function does not appear to affect a newborn's thyroid function at birth, nor does lower neonatal thyroid function within the normal range impact a child's cognition," said Dr. Pearce. "These findings were unexpected. We look forward to the results of trials currently ongoing in the U.S. and Europe to better elucidate the relationship between mild maternal hypothyroidism and child cognition."
About the American Thyroid Association (ATA)The American Thyroid Association (ATA) is the lead organization in promoting thyroid health and understanding thyroid biology. The ATA values scientific inquiry, clinical excellence, public service, education, collaboration, and collegiality.
A non-profit medical society founded in 1923, the ATA fulfills its mission through supporting excellence and innovation in research, clinical care, education, and public health. ATA members are physicians and scientists who work to enhance the understanding of thyroid physiology and pathophysiology, improve the diagnosis and treatment of thyroid diseases, and promote the education of physicians, patients, and the public about thyroid disorders.
Thyroid diseases are among the most common disorders of the endocrine system, affecting almost 13 million Americans alone. The ATA has extensive online information for patients on thyroid disease (in English and Spanish) serving the clinician as a resource for patients and the public who look for reliable information on the internet.
To learn more about the ATA, visit: http://www.thyroid.org.
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