Women with thyroid disease are more likely have babies with birth defects even if tests show no problem with the gland during pregnancy.
A study by Johns Hopkins University also showed that babies born to women with overactive or underactive thyroid were at increased risk of heart, brain or kidney defects. They were also more likely to have other anomalies, including cleft lip or palate, or extra fingers.
In addition, infants born to women with underactive thyroid were at increased risk of cardiac problems even if the mothers were on medication. The new research contradicts some earlier studies indicating thyroid disease did not pose fetal risks.
However, those studies were conducted using less sophisticated technology for detecting birth defects. Dr Nagey recommends that doctors consider adding thyroid testing to the routine prenatal diagnostic tests.
If the test indicates the woman has hypothyroidism, a foetal echocardiogram during the 20th week of pregnancy might be warranted.
The researchers studied 101 women (64 with hypothyroidism and 50 with the overactive version, hyperthyroidism) who gave birth at The Johns Hopkins Hospital between December 1994 and June 1999.
Overall, there were 108 pregnancies with 114 fetuses.
Twenty-one babies (18%) had birth defects, including problems in the cardiac, renal and central nervous systems and other disorders such as sunken chest, extra fingers, cleft lip and palate, and ear deformities. Two fetuses died before being delivered.
The women with hypothyroidism were more likely than those with hyperthyroidism to have babies with defects.
Researchers believe it is possible the same antibodies that cause the underactive thyroid also could be responsible for the birth defects.
Annual Meeting Of The Society For Maternal-Fetal Medicine In New Orleans January 20, 2002
Even a mild, symptom-free case of thyroid deficiency in a pregnant woman can affect her child’s IQ scores years later. Overall, compared with other children, the offspring of thyroid-deficient mothers had impaired school performance and lower scores on tests of attention, language, and visual-motor performance.
Screening women for thyroid problems should be part of routine prenatal testing because it could help to reduce miscarriages, since new research has shown that pregnant women with underactive thyroid glands have a four-fold increased risk of miscarriage in the second three months of pregnancy than other women.
If you are pregnant it will be important to get your thyroid function tested. There are several ways you can do this. One needs to measure FREE hormone levels in addition to a TSH level. Be sure and use the far more sensitive Free T3 and Free T4 when you test as this and the modified TSH reference range (above 1.5 – abnormal) will pick up many cases of low thyroid, but not all. It is not uncommon to see a patient with a compromised thyroid, yet all the blood tests come back as “euthyroid”, meaning “well thyroid”.
BUT – if levels are low, or if the patient is experienceing signs and/or symptoms of underactive thyroid, one should consider going onto a 6 month course of Dr. Wilson’s unique product called Thyro-Balance. This comprehensive liquid formula will assist in optimising a female’s thyroid function during a critical phase of the child’s development.
Eric Bakker ND