Can Thyroid Imbalance in Pregnancy Raise Autism Risk?

Can a mother’s thyroid levels during pregnancy influence her child’s risk of autism? A major new study says yes, but only when the imbalance persists across multiple trimesters.

Researchers from Israel analyzed over 51,000 births and found that women whose thyroid hormone levels remained unstable throughout pregnancy were more likely to have children diagnosed with autism spectrum disorder (ASD). However, here’s the key: women whose thyroid disease was well-controlled did not face a higher risk (1^✔ ✔Trusted Source
Maternal Thyroid Dysfunction During Pregnancy as an Etiologic Factor in Autism Spectrum Disorder: Challenges and Opportunities for Research

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Why Thyroid Hormones Matter for Baby’s Brain

Thyroid hormones play a central role in early fetal brain development. They help guide:

• neural growth
• brain wiring
• cognitive and emotional development

Even mild, ongoing disruption can affect how the fetal brain forms and functions. “Persistent thyroid imbalance, not the diagnosis itself, is what raises the risk,” explains lead author Idan Menashe, PhD, of Ben-Gurion University.

What the Study Found

Tracking pregnancies across three trimesters, researchers discovered:

Persistent Imbalance Raises Autism Risk

Mothers who had abnormal thyroid hormone levels across multiple trimesters were more likely to have children with autism.

Adequate Treatment Offers Protection

Women with chronic thyroid disease but well-controlled levels did not have an increased risk.

Longer Hormone Imbalance, Higher the Risk

A clear dose-response pattern emerged; the more trimesters affected, the higher the risk.

These findings highlight a simple but critical takeaway: Monitoring thyroid levels throughout pregnancy is essential, not just once.

Why This Matters for Expectant Mothers

Thyroid disorders are common in pregnancy, and many women require dose adjustments as the body’s hormone needs rise. This study suggests that early testing, repeat monitoring, and timely medication adjustments may help protect fetal brain development.

The Bottom Line

This research does not mean thyroid disorders cause autism. But it does strengthen the idea that unstable thyroid hormone levels, especially when prolonged, may influence a child’s neurodevelopment. For pregnant women with hypothyroidism or hyperthyroidism, the message is clear:

Track it. Treat it. Keep levels stable.

It may be one of the quietest yet most impactful ways to support your baby’s developing brain.

Reference:

1. Maternal Thyroid Dysfunction During Pregnancy as an Etiologic Factor in Autism Spectrum Disorder: Challenges and Opportunities for Research - (https://pmc.ncbi.nlm.nih.gov/articles/PMC10884547/)

Source-Medindia