Hidden Thyroid Issues in Pregnancy Could Mean Thyroid Trouble Later

Key Takeaways

• New research shows that asymptomatic thyroid disease in pregnancy is a strong predictor of full-blown hypothyroidism years later

• The risk rose fourfold for women with 'subclinical' hypothyroidism detected in pregnancy

• There was no such link when it came to hypothyroxinemia, a deficiency in the thyroid hormone thyroxine

TUESDAY, Aug 6, 2024 (HealthDay News) -- Women who develop subclinical thyroid issues during pregnancy, meaning symptoms haven't surfaced, could face real thyroid trouble within five years, a new study finds.

Pregnant women who were diagnosed with subclinical hypothyroidism, pointing to an under-active gland, before 21 weeks of gestation had four times the odds of developing symptomatic hypothyroidism later, a team at University of Utah Health discovered.

These women also had a fourfold greater odds of requiring thyroid replacement therapy within five years of delivering a child, the team reported recently in the journal Thyroid .

The researchers noted that subclinical hypothyroidism has long been known to be common during pregnancy, with as many as 1 in every 4 pregnant women thought to be affected.

Subclinical hypothyroidism isn't by itself harmful, but symptomatic "overt" hypothyroidism can be linked to fatigue, depression and even heart problems, said a team led by Dr. Michael Varner , a professor of obstetrics and gynecology at the university's school of medicine.

Their study included 307 pregnant women who'd been diagnosed with either subclinical hypothyroidism or hypothyroxinemia, a condition where too low a level of the thyroid hormone thyroxine is found in the blood.

These conditions were detected between eight and 20 weeks gestation and, "at 1 and 5 years after delivery, participants were asked whether they had either been diagnosed with or were being treated for a thyroid condition."

In contrast to the links between hypothyroidism and later thyroid issues, women who had hypothyroxinemia during pregnancy did not have any higher long-term risk for hypothyroidism, the researchers said.

According to Varner, the trials that his team drew on for this study also showed "showed no difference in five-year neurodevelopmental outcomes in children from prenatal treatment of either subclinical hypothyroidism or hypothyroxinemia."

However, when it came to mom's health, "our data lend further evidence to the postpartum time period as a time when autoimmune diseases, in this case, hypothyroidism, are more likely to be present," Varner said in a university news release.

More information

Find out more about thyroid disease in pregnancy at the National Institute of Diabetes and Digestive and Kidney Disease.

SOURCE: University of Utah Health, news release, Aug. 2, 2024

What This Means For You

Women who develop a pre-symptomatic form of thyroid disease while pregnant face much higher odds of full-blown hypothyroidism years later.