Controlled Antenatal Thyroid Screening Study III: Effects of Gestational Thyroid Status on Brain Microstructure

Area of Science:

• Neuroscience
• Endocrinology
• Developmental Biology

Background:

• Maternal thyroid dysfunction during pregnancy poses risks to fetal neurodevelopment.
• The impact of suboptimal gestational thyroid function (SGTF) on adolescent brain microstructure remains largely unknown.
• Understanding these effects is crucial for identifying potential interventions.

Purpose of the Study:

• To investigate the association between SGTF and white matter microstructure in adolescents.
• To determine if maternal levothyroxine supplementation during pregnancy affects adolescent brain development.
• To explore correlations between maternal thyroid hormone levels and brain microstructure.

Main Methods:

• The Controlled Antenatal Thyroid Screening (CATS) study utilized magnetic resonance imaging (MRI), including diffusion MRI and quantitative magnetization transfer (qMT) imaging.
• Seventy-five children aged 11-16 years with varying gestational thyroid function (untreated SGTF, normal GTF, treated SGTF) were analyzed.
• Microstructural integrity of white matter tracts was assessed.

Main Results:

• Untreated SGTF was significantly associated with reduced axonal integrity in the inferior longitudinal fasciculus compared to normal gestational thyroid function.
• This alteration in white matter microstructure was observed in adolescents whose mothers had SGTF.
• No significant associations were found for secondary outcomes after multiple comparison corrections.

Conclusions:

• Suboptimal gestational thyroid function is linked to specific alterations in adolescent white matter microstructure.
• Levothyroxine treatment during pregnancy may mitigate or reverse these microstructural changes.
• These findings highlight the importance of managing maternal thyroid function for optimal child neurodevelopment.