Researchers from UK say that, babies of mother's with hypothyroidism are likely to have a low IQ. The thyroid gland secretes hormones which control metabolism, growth and development. Symptoms hypothyroidism include tiredness, dry skin and weight gain.
Children born with an underactive thyroid gland can suffer learning difficulties. Pregnant women with the condition are more prone to a potentially life-threatening condition called pre-eclampsia and to have their babies prematurely. Because foetuses' thyroid glands do not kick into action until the middle trimester of pregnancy, they are reliant on their mother in the early stages.
The researchers from the Foundation for Blood Research in Scarborough, Maine, say even when pregnant women have a mildly underactive thyroid gland and show no symptoms, IQ can be affected.
The researchers, led by Dr James Ludwik, studied children aged six to ten and compared those born to 124 women with a normal thyroid gland with children born to 62 women with an underactive gland.
Some 22% of the children whose mothers had an underactive thyroid had IQs of 80 or lower. The researchers say: "Hypothyroidism in pregnant women can adversely affect their child's subsequent performance on neuropsychological tests. "