Thyroid Test: Bad at maths? Blame mom

22 September 2014 - 02:00 By Laura Donnelly, ©The Daily Telegraph
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A new study suggests a link between certain personality traits and your likelihood of having a child.
A new study suggests a link between certain personality traits and your likelihood of having a child.
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Children who are not good at maths could blame their mothers, a study suggests.

Five-year-olds who had been exposed to low levels of thyroid hormones while in the womb were almost twice as likely to do badly in arithmetic tests as those whose mothers had normal levels.

Low thyroid levels can be caused by a shortage of iron, a common feature of pregnancy.

Pregnant women undergo regular blood tests to check their levels and are advised to eat plenty of lean meat, green leafy vegetables and dried fruit and nuts to avoid problems. Some are advised to take supplements. Low levels of the hormone are also more common in those with a family history of the disease, and among those with other health problems, such as anaemia and type 1 diabetes, and those with a family history of thyroid conditions.

Researchers from the VU University Medical Centre in Holland studied almost 1200 children from birth to age five when they assessed their test scores for language and arithmetic. They also monitored the mothers' hormone levels when they were 12 weeks' pregnant. Youngsters born to mothers with low levels of thyroxine were found to have lower test scores in arithmetic but their language tests were not affected.

"Whether these problems persist into adulthood remains to be seen," said Dr Martijn Finken, the lead author, whose findings were presented at the European Society for Paediatric Endocrinology's annual meeting in Dublin. "We will continue to follow these children to answer this next big question."

Previous studies found that undetected or inadequately treated hypothyroidism in mothers was associated with IQ changes in infants. The average IQ scores were about four points lower in the children of mothers with an underactive thyroid than in children of normal mothers. The children were also more likely to have difficulty in school.

In adulthood, underactive thyroids can cause tiredness, sensitivity to cold, weight gain, depression, pain and numbness. About one woman in 50 and one man in 1000 develops hypothyroidism at some stage in life.

Some women develop thyroid imbalance during pregnancy.

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