Controlled Antenatal Thyroid Screening II: Effect of Treating Maternal Suboptimal Thyroid Function on Child Behavior.

Area of Science:

• Obstetrics and Gynecology
• Pediatric Neurology
• Endocrinology

Background:

• Suboptimal gestational thyroid function (SGTF) is a concern during pregnancy.
• Observational studies suggest a link between SGTF and increased risk of autism spectrum disorder (ASD) and attention-deficit/hyperactivity disorder (ADHD) in children.
• The Controlled Antenatal Thyroid Screening (CATS) study was the first randomized controlled trial to examine the effects of treating SGTF on child neurodevelopment.

Purpose of the Study:

• To investigate the impact of treating maternal suboptimal gestational thyroid function (SGTF) on child behavioral outcomes, including symptoms of ASD and ADHD.
• To analyze the association between maternal thyroid hormone levels during pregnancy and neurodevelopmental outcomes in offspring.
• To assess the safety and efficacy of thyroxine supplementation in pregnant individuals with SGTF.

Main Methods:

• The CATS study enrolled 475 mothers.
• Mothers completed validated questionnaires (SDQ, Child ADHD, SCQ) regarding their children's behavior (mean age 9.5 years).
• Children were categorized into normal gestational thyroid function (GTF), treated SGTF, and untreated SGTF groups. Comparisons included total scores, clinical threshold exceedance, and effects of maternal "overtreatment" (high FT4).

Main Results:

• No significant differences in overall behavioral scores were found between normal GTF, treated SGTF, and untreated SGTF groups.
• Children of mothers who were "overtreated" (excessively high maternal FT4) showed significantly higher rates of behavioral difficulties.
• Specifically, overtreatment was associated with increased scores for conduct problems (SDQ), ASD screening (SCQ), and ADHD hyperactivity symptoms compared to normal GTF and untreated SGTF groups.

Conclusions:

• There was no overall association between treating suboptimal gestational thyroid function (SGTF) and adverse behavioral outcomes in offspring.
• Maternal "overtreatment" with thyroxine during pregnancy was linked to a significant increase in ADHD symptoms and behavioral difficulties in children.
• Thyroxine supplementation in pregnancy necessitates careful monitoring to prevent overtreatment and potential negative neurodevelopmental effects.