Maternal Thyroid Function Not Associated With Emotional, Behavioral Problems in Offspring

Maternal thyroid function was not found to be associated with emotional or behavioral problems in offspring, according to a study published in European Child & Adolescent Psychiatry.

Investigators abstracted data from the Avon Longitudinal Study of Parents and Children, a longitudinal birth cohort study of pregnant women in Avon, United Kingdom, who had a delivery date in 1991 through 1992. The present study included data on all mother-child pairs with complete thyroid function data obtained during the first trimester of pregnancy. Data included levels of thyroid-stimulating hormone, free thyroxine, and thyroid peroxidase antibodies. Childhood emotional and behavioral problems were captured with the Strengths and Difficulties Questionnaire, which was completed by parents when their child was 42 months, 81 months, 9 years, and 11 years of age.

A group-based trajectory modelling approach identified different patterns of emotional and behavioral problems at each follow-up time point. Multinomial logistic regression was performed to identify any associations between thyroid hormone levels and offspring trajectories.

Data from 4839 mother-child pairs (mean maternal age, 28.1±4.8; 51.6% male offspring) were used in analyses. The majority of mothers had normal thyroid function. The authors identified 4 trajectories of offspring emotional and behavior problems: normative-decreasing (49.7%), moderate-decreasing (35.7%), moderate-static (8.4%), and high-decreasing (6.2%). The normative-decreasing and moderate-decreasing groups represented children with slightly elevated total difficulty scores at 42 months but lower scores at later ages. The moderate-static group displayed consistent slightly elevated total difficulty scores. The high-decreasing group had very high total difficulty scores at 42 months and continued to score high during follow-up. No association was observed between maternal thyroid function and offspring trajectories. However, offspring of mothers with lower educational level (34.5%) and mothers who never married (29.3%) were overrepresented in the high-decreasing group. Additionally, 61.4% of mothers in the high-decreasing group had smoked during pregnancy, and 19.3% reported antenatal depression.

Abnormal thyroid function was found to have no effect on offspring emotional and behavioral trajectory, while adverse prenatal conditions may play an important role. The study suggests that other maternal risk factors may be more effective targets for intervention. The investigators noted that thyroid function was observed only during the first trimester, and maternal thyroid parameters may have changed across trimesters and after pregnancy. Additionally, they stated that detection of hypothyroidism in pregnant women remains important, and that these data do not discount the utility of prenatal thyroid function monitoring. 

Reference

Fetene DM, Betts KS, Scott JG, Alati R. Maternal prenatal thyroid function and trajectories of offspring emotional and behavioural problems: findings from the ALSPAC cohort [published online September 16, 2019]. Eur Child Adolesc Psychiatry. doi:10.1007/s00787-019-01404-7