This article is more than 5 years old. Information may no longer be current.
No link found between newborn thyroid function, cognitive development
Click Here to Manage Email Alerts
79th Annual Meeting of the ATA
CHICAGO — Newborn thyroid function within the normal range was not associated with cognitive development or with maternal thyroid function in a recent study presented at the 79th Annual Meeting of the American Thyroid Association.
Researchers from Harvard Medical School and other sites in Boston studied children born between 1993 and 2003 at 34 weeks of gestation or older (n=500) to examine the relationship between thyroxine levels in newborns and first trimester maternal thyroid function and cognition in childhood.
The mean newborn T4 was 17.6 mg/dL, according to the researchers. Levels were 1.07 mg/dL greater in girls (95% CI, 0.38-1.76) and 0.43 mg/dL greater in infants born after longer gestation (95% CI, 0.18-0.69).
When adjusted for maternal and child characteristics, higher newborn T4 was associated with lower scores on the visual recognition memory test among infants aged 6 months (–0.5; 95% CI, –0.9 to –0.2), according to the researchers. However, at age 3 years researchers did not find this association with scores on the Peabody Picture Vocabulary Test and the Wide Range Assessment of Visual Motor Ability test.
“In this sample from an iodine sufficient area, first trimester maternal thyroid function did 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,” Elizabeth N. Pearce, MD, assistant professor of medicine at Boston University School of Medicine, said in a press release.
“These results were unexpected; we look forward to the results of trials currently ongoing in the United States and Europe to better elucidate the relationship between mild maternal hypothyroidism and child cognition.” – by Christen Haigh
Prior studies, from regions in Europe with marginal iodine sufficiency, suggest that maternal thyroid hormone levels, specifically low total T4 levels in early pregnancy, are associated with impaired cognitive function in childhood. This study, from Eastern Massachusetts, which is an iodine-sufficient region, did not show a correlation between maternal function early in gestation and newborn thyroid function. Moreover, as long as newborns had normal T4 levels — even in the lower end of the normal range — cognitive development was normal when tested at 3 years of age.
– Jeffrey R. Garber, MD
Endocrine Today Editorial Board member
For more information:
- Oken E. #238. Presented at: 79th Annual Meeting of the American Thyroid Association; Oct. 1-5, 2008; Chicago.