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Am J Perinatol 2021; 38(02): 191-201
DOI: 10.1055/s-0040-1717073
Original Article

Maternal Hypothyroidism Increases the Risk of Attention-Deficit Hyperactivity Disorder in the Offspring

Morgan R. Peltier
1   Department of Foundations of Medicine, NYU-Long Island School of Medicine, Mineola, New York
2   Department of Obstetrics and Gynecology, NYU-Winthrop Hospital, Mineola, New York
,
Michael J. Fassett
3   Department of Obstetrics and Gynecology, Kaiser Permanente West Los Angeles Medical Center, Los Angeles, California
,
Vicki Y. Chiu
4   Department of Research and Evaluation, Kaiser Permanente Southern California, Pasadena, California
,
Darios Getahun
4   Department of Research and Evaluation, Kaiser Permanente Southern California, Pasadena, California
5   Department of Health Systems Science, Kaiser Permanente Bernard J. Tyson School of Medicine, Pasadena, California
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Abstract

Objective This study aimed to determine if hypothyroidism prior to, or during, pregnancy increases the risk of attention-deficit hyperactivity disorder (ADHD) in the child and how the association may be modified by preterm birth, sex of the child, and race-ethnicity.

Study Design Data were abstracted from linked maternal–child medical records. Incidence rate differences (IRDs), adjusted hazard ratios (aHRs), and their 95% confidence intervals (CIs) were estimated to evaluate the association of maternal hypothyroidism with childhood ADHD risk. Stratified analyses were used to evaluate whether the association is affected by timing of first diagnosis, gestational age at birth (term vs. preterm), sex, and race-ethnicity.

Results Hypothyroidism diagnosed prior to (IRD = 1.30), or during (IRD = 0.59) pregnancy increases the risk of ADHD in the children (aHR = 1.27; 95% CI: 1.15, 1.41, and 1.17; 95% CI: 1.00, 1.38). The association was strongest when diagnosed during the first trimester (IRD = 0.97 and aHR = 1.28; 95% CI: 1.04, 1.58). For children born preterm, there was significantly increased risk of ADHD if their mothers were diagnosed prior to (IRD = 3.06 and aHR = 1.43; 95% CI: 1.09, 1.88), but not during pregnancy. The effect of maternal hypothyroidism on increased risk of ADHD was stronger for boys (IRD = 1.84 and aHR = 1.26; 95% CI: 1.14, 1.40) than it was for girls (IRD = 0.48 and aHR = 1.19; 95% CI: 1.01, 1.40) and for Hispanic children (IRD = 1.60 and aHR = 1.45; 95% CI: 1.25, 1.68) compared with other race ethnicities.

Conclusion Exposure to maternal hypothyroidism during the periconceptual period significantly increases the risk of ADHD and that the association varies with gestational age at delivery, child sex, and race-ethnicity.

Key Points

  • Maternal hypothyroidism increases the risk of ADHD diagnosis in the offspring.

  • The association of maternal hypothyroidism with childhood ADHD was influenced by timing of diagnosis.

  • Strength of the association was strongest in preterm born infants, boys, and Hispanic children.

Keywords

attention-deficit hyperactivity disorder - ADHD - hypothyroidism neurodevelopment - pregnancy - preterm birth - thyroid

Supplementary Material



Publication History

Received: 20 December 2019

Accepted: 22 August 2020

Article published online:
21 October 2020

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