Thyroid problems in mother affect newborn
There is an increased risk of neurological development problems in infants born to mothers who had low levels of thyroid hormone early in pregnancy, according to a report in the medical journal Pediatrics.
The results indicate that low thyroid hormone levels in the mother, even if they don’t cause any symptoms, can have important neurological development consequences in the newborn, lead author Dr. Libbe Kooistra, from the University of Calgary in Alberta, Canada, told Reuters Health. The question now is whether the magnitude of these problems warrants implementation of maternal thyroid screening programs, he added.
In previous studies, Kooistra’s team had shown that low levels of thyroid hormone during early pregnancy affect neurological development in children who were several months of age. Critics, however, had suggested that by that age, other factors may have contributed to the problems, he said. This led Kooistra’s group to look at the effects in newborns, since many of the potentially contributing factors would not yet be present.
In the new study, the Neonatal Behavioral Assessment Scale (NBAS) was conducted on 108 infants born to mothers who had low thyroid hormone levels at 12 weeks’ pregnancy and in a comparison group of 96 infants. Maternal thyroid function was also evaluated at 24 and 32 weeks’ pregnancy.
Infants of mothers with low thyroid hormone levels scored significantly lower on certain parts of the NBAS than did infants born to mothers with normal levels. However, only thyroid hormone levels at 12 weeks’ pregnancy correlated with NBAS scores; maternal thyroid function later in pregnancy seemed to have no effect on infant outcomes.
Kooistra noted that the merits of routine thyroid screening in pregnant women are now being debated. Coupled with past research linking low thyroid hormone levels with obstetric complications and hyperactivity in the child, the current findings suggest that thyroid screening may be worthwhile, he added.
SOURCE: Pediatrics, January 2006.
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