Can Thyroid Screening During Pregnancy Protect Your Baby?

Experts have been debating the benefits of universal thyroid testing in pregnant women.
Clinicians have debated the concept of universal thyroid testing in pregnant women for quite some time now. While it may help to lower complications and protect fetal brain development, others say it could lead to overdiagnosis among other risks.
A recent analysis published in Frontiers in Endocrinology presents the pros and cons of universal testing.The authors note that optimal thyroid hormone levels have been proven to maintain pregnancy and aid in fetus development. Thyroid dysfunction is common in women of childbearing age. It can result in substantial adverse obstetric and child neurodevelopmental outcomes. It is easy to detect via blood testing and can be corrected with inexpensive and available treatments, they say.
“Screening only high-risk patients appears to miss the majority of cases, and economic models show that compared to high-risk screening, universal screening is cost effective even if only overt hypothyroidism was assumed to have adverse obstetric effects,” they stated in the paper.They say that fetuses are completely reliant on maternal thyroid hormones up to 16 weeks, which is a critical time in brain development. Too much or too little of the right thyroid hormones can lower the baby’s IQ later in life. It also raises the risk of premature birth, preeclampsia and other complications.“Economic models show that universal screening is the most cost-effective approach, even if only obvious hypothyroidism (profoundly low thyroid hormone level) — which is often missed by case-finding — affects pregnancy and brain development,” said Peter Taylor, lead author and a professor at Cardiff University in Wales.
The debate over universal thyroid screening
In the United States, doctors tend only to screen women at high risk for thyroid dysfunction or those who have a history of autoimmune diseases or preterm deliveries.
Doctors tend to debate the screening based on cases when a women has no symptoms or abnormal or borderline thyroid tests. Treating borderline cases detected via a universal screening could risk patient anxiety and puts pressure on clinicians. Most noted is that evidence is lacking when it comes to the benefits of treating women with abnormal and borderline test results.
On the flip side, Taylor said that universal thyroid screening in early pregnancy could improve child IQ and reduce complications of pregnancy.
“However, a consensus is unlikely to be reached without further controlled trials which recruit women pre-conception or as early as possible in pregnancy,” he added.