The risk of developing attention deficit hyperactivity disorder (ADHD) was increased in children exposed to maternal hypothyroidism during the periconceptual period. These results from a retrospective review of the medical records were published in the American Journal of Perinatology.
The medical records of 329,157 births between 2000 and 2016 in the Kaiser Permanente Southern California database were analyzed. All diagnoses were made using the International Classification of Diseases.
A total of 16,696 children were diagnosed with ADHD, while 312,461 were not. Women who gave birth to a child with ADHD tended to be younger (P <0.001), finished high school (P <0.001), earned <$ 30,000 per year (P <0.001), and were nulliparous (P <0.001). Giving premature birth (P <0.001) and smoking tobacco during pregnancy (P <0.001).
Of all pregnancies, 2.9% had diagnosed hypothyroidism within 120 days before or during pregnancy. The risk of having ADHD diagnosed in children of women with a diagnosis of hypothyroidism was increased (adjusted hazard ratio) [aHR]1.24; 95% CI, 1.14-1.35). However, the increased risk was not seen in women who did not treat their hypothyroidism or who received low dose (<50 ug / d) thyroid supplementation (aHR, 1.08; 95% CI, 0.75-1.57).
Higher doses of maternal thyroid supplement significantly increased the risk of ADHD (aHR, 1.26; 95% CI, 1.14-1.39).
The risk of being diagnosed with ADHD was increased in children born to women diagnosed with hypothyroidism 61 to 120 days prior to pregnancy and who gave birth prematurely (aHR, 1.42; 95% CI, 1.01 to 1.99), women who were diagnosed prior to pregnancy and gave birth to a boy (aHR, 1.30; 95% CI, 1.15-1.46), women who were 1-60 days a diagnosis was made prior to pregnancy and who were not Spanish White (aHR, 1.57; 95% CI, 1.24-2.00); or women diagnosed in the first trimester who were of Hispanic descent (aHR, 1.71; 95% CI, 1.25-2.33).
This study may have been constrained by underlying biases in diagnosing ADHD in minority children. These data showed that non-Hispanic white children were at increased risk for ADHD, although the lower diagnosis rate in non-white children may have resulted in an underestimated risk.
The study’s authors concluded that children born to women who were diagnosed with hypothyroidism within a few months or during early pregnancy and who should be treated for symptoms were at increased risk of having a baby who would eventually be diagnosed with ADHD.
Future studies stratifying women according to their type of hypothyroidism are needed to better understand the possible molecular mechanisms causing the link between hypothyroidism and ADHD.
MR Peltier, MJ Fassett, V Chiu et al. Maternal hypothyroidism increases the risk of attention deficit hyperactivity disorder in the offspring [published online October 21, 2020]. Am J Perinatol. doi: 10.1055 / s-0040-1717073
This article originally appeared on Endocrinology Advisor