Prenatal Thyroid Testing

The Important Of The Thyroid Gland

The thyroid gland, while not readily top-of-mind when a woman is considering pregnancy, has a great influence on the pregnancy, the woman, and the unborn baby. This gland generates the hormones that govern metabolism, helping to regulate body weight, core temperature, heart rate and myriad other functions.

If the thyroid malfunctions, then either too much (hyperthyroidism) or too little (hypothyroidism) of these vital hormones are released. In pregnancy, these conditions may lead to miscarriage, premature birth, or pre-eclampsia. In the case of hypothyroidism, a child may be born with impaired intelligence.

Hypo- and Hyper-thyroidism

The symptoms of hypothyroidism exhibit signs of fatigue, weight gain, and dry skin, all of which are commonly present during pregnancy. The symptoms of this condition are subtle and can easily be masked in pregnancy. Unless testing is done, the condition may go undiagnosed. The symptoms of hyperthyroidism, poor sleep, weight loss and nervousness after birth, are also reflected in other post-partum conditions. Again, unless the proper blood testing has been done and the condition monitored, it goes undiagnosed and can potentially cause problems for both mother and baby.

Hypothyroidism, low thyroid function, is often generated by an underlying autoimmune disease and is seen more frequently than hyperthyroidism. Up to 20 percent of women of reproductive age test positive for antibodies that attack the thyroid gland and may eventually destroy it. The risk of miscarriage in such women is doubled. Hypothyroidism can also harm fetal brain development. However, if the condition is identified and treated, the baby is not impaired.

Selective Screening.....

Most medical societies endorse only selective screening for thyroid-stimulating hormone (TSH), focusing mainly on women who have a personal history of thyroid malfunction or have it in their family history. Women with Type 1 diabetes or autoimmune disease, or those who have had a previous miscarriage or premature delivery, are also candidates for screening.

Or Universal Screening?

However, more and more endocrinologists are suggesting that prenatal TSH testing be done on all women who are considering pregnancy or who are pregnant. Advocates for universal screening say that the evidence is overwhelming that a shortage of thyroid hormone in the mother adversely affects the baby. Some organizations feel that universal screening is premature and that more data is needed to justify universal screening. As a result, clinical trials are underway in Wales and in the US, both with the intent of confirming the effects of underactive thyroid function on I.Q. and the effects of treatment versus non-treatment.

For many doctors, screening for TSH is a given for pregnant women. Prompt treatment of thyroid disease may ease the pregnancy symptoms for the mother and help to protect the baby. Although there are cautions on both sides of the equation, Dr. Alex Stagnaro-Green, an endocrinologist at Touro University College of Medicine in Hackensack, N.J. stated, "My belief is that data will be forthcoming that will push us towards universal screening."