Abnormal thyroid hormones in pregnancy linked to behavioral problems in boys

Maternal free T4 levels during pregnancy influence behavioral problems in boys

06 January 2022

2 minute read

Disclosures: The authors report no relevant financial information.

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According to data from a study published in Jhe Journal of Clinical Endocrinology and Metabolism.

“Our results underscore the importance of close monitoring and management of maternal thyroid function during pregnancy,” Kun Huang, PhD, from the Department of Maternal, Child and Adolescent Health at Anhui Medical University School of Public Health in China, said in a press release. “This research presents a new perspective in the early intervention of children’s emotional and behavioral problems.”

Maternal Free T4 Levels During Pregnancy Influence Behavioral Problems in Boys
Maternal free T high or low4 during pregnancy is associated with an increased risk of behavioral problems in preschool boys. Data are from Li P, et al. J Clin Endocrinol Metab. 2022; doi:10.1210/clinem/dgab887.

Researchers recruited 1,860 pregnant women who had their first prenatal checkup at Ma’Anshan Maternal and Child Health Hospital in China from May 2013 to September 2014. All participants were within 14 weeks of pregnancy at the time of their first examination, had no mental illness and were willing to participate in the follow-up of their children. Blood samples were taken during each trimester of pregnancy to measure thyroid hormones. Women were placed in a high, moderate, or low level group for thyroid-stimulating hormone, free thyroxine, and thyroid peroxidase based on trajectories during pregnancy. At the child’s average age of 4 years, caregivers completed Achenbach’s Child Behavior Checklist to assess behavior problems. The checklist included three summary scales: Internalizing Problems, Externalizing Problems, and Total Problems. Internalizing issues included emotional reactivity, anxiety/depression, and withdrawal. Externalizing problems included attention problems and aggressive behavior.

Among the participants, 67.8% had a low TSH level, 27.8% had a moderate level and 4.4% had a high level. Free T4, 33% of women had a low level, 52.4% had a medium level and 14.6% had a high level. Maternal thyroid peroxidase antibodies were low and stable for 96.5% of participants and high and falling for 3.5%.

For preschool boys, the prevalence of externalizing behavior problems was highest among those whose mother was in the high TSH group and lowest among those whose mother was in the low TSH group. Anxious/depressed feelings were highest in boys whose mothers were in the high free T4 group and lowest among boys whose mothers are in the moderate free T4 group.

After adjusting for confounders, maternal elevated TSH was associated with an increased likelihood of weaning (adjusted OR = 2.01; 95% CI, 1.16-3.5) and externalizing problems (aOR = 2.69; 95% CI, 1.22-5.92) in boys. Moderate TSH during pregnancy was associated with an increased risk of aggressive behavior in boys (aOR = 3.76; 95% CI, 1.16-12.23). High free T4 during pregnancy increased the risk of anxious/depressive feelings (ORa = 2.22; 95% CI, 1.08-4.56) and total problems in boys (ORa = 1.74; 95% CI, 1.13-2.66), while a low free T4 was associated with increased aggressive behavior in boys (aOR = 4.17; 95% CI, 1.22-14.24). No association was observed between maternal thyroid hormone levels and emotional or behavioral problems in daughters.

The researchers said it is unclear why maternal thyroid hormones are associated with behavioral changes in boys and not girls, but there is evidence that the interaction between thyroid hormones and sex steroid hormones may be more direct with boys.

“Thyroid hormones are believed to be associated with testicular development, growth, and maturation,” the researchers wrote. “They will enhance gonadotropin-induced androgen synthesis and release in the testes. Experimental studies have indicated that thyroid hormone is essential for typical male brain development. We suspect that boys may be more susceptible to alterations in maternal thyroid hormones and therefore subsequent behavioral problems.