Should pregnant women be screened for thyroid disease?

Pregnant women should be screened for thyroid problems, a new study suggests.

Researchers from the Charles University in Prague, Czech Republic, found that more than a third of pregnant women with antibodies in their blood to thyroid peroxidase (TPO) go on to develop abnormal thyroid hormone levels within two years of giving birth.

The enzyme thyroid peroxidase plays a major role in the production of thyroid hormones. Abnormal thyroid hormone levels can indicate thyroid disease.

Although TPO antibodies are found in around 13 per cent of women, most of whom will remain healthy, past studies have linked a positive test during pregnancy to obstetric and thyroid problems in some women.

In the study, the researchers tracked nearly 189 women who had shown some form of thyroid disorder in the first trimester of pregnancy. One hundred tested positive for the TPO antibody, but showed no signs of thyroid problems.

However, when retested almost two years later, 35 per cent of these women had abnormal levels of thyroid stimulating hormone (TSH), which stimulates the pituitary gland to secrete the hormones thyroxine (T4) and triiodothyronine (T3). If the levels of these hormones are too low or too high, it can lead to hypothyroidism or hyperthyroidism.

Dr Eliska Potlukova, who led the study, said: “This is a potentially important finding, because it affects so many women. Roughly one in seven pregnant women will test positive for the TPOAb antibody, and we have now found that more than a third of these will go on to develop thyroid problems within two years of giving birth.

"This is rather surprising, as these positively screened women should have been referred to an endocrinologist already in pregnancy. Thus, in general population, this number would be much higher. That means a lot of women – perhaps tens of thousands in one of the larger European countries - who will have thyroid problems which could be detected earlier."

The findings were presented at the European Congress of Endocrinology in Rotterdam.

This article was published on Wed 4 May 2011