Maternal thyroid dysfunction and stress during pregnancy on ADHD risk in preschoolers: a retrospective study

To estimate the prevalence of attention-deficit/hyperactivity disorder (ADHD) in preschool children and to examine the relationship between ADHD and pregnancy-related factors across different trimesters in mothers.

The retrospective cohort study enrolled mother-child pairs from 20 kindergartens in the Longhua district, Shenzhen City, China. Adjusted Cox proportional-hazard models were used to estimate hazard ratio (HR) for the risk of pregnancy-related factors on ADHD.

Among 5602 mother-child pairs, 220 mothers (3.9%) were diagnosed with thyroid dysfunction, and 553 (9.9%) children aged 3-7 years were diagnosed with ADHD. In the adjusted model, children of mothers with thyroid dysfunction during pregnancy had a 54.1% higher risk of an ADHD diagnosis (95% CI: 1.050, 2.262) compared to those whose mothers did not have thyroid dysfunction. Higher maternal stress levels during the first trimester of pregnancy are associated with an increased risk of offspring developing ADHD. Compared to children whose mothers experienced significant stress in the first trimester of pregnancy, those whose mothers experienced moderate and minor stress had 36.3% and 42.9% lower risk of ADHD diagnosis, respectively (HR = 0.637, 95%CI: 0.487,0.834 for moderate; HR = 0.571 95% CI: 0.391, 0.833 for minor). However, stress during the second and third trimesters was not significantly associated with the risk of ADHD.

The study demonstrates the need for early ADHD screening in preschoolers and continuous monitoring of maternal thyroid hormone and stress levels during pregnancy. It also emphasizes the importance of implementing preventive and management strategies as part of holistic care for both preschoolers and expectant mothers.