Childhood IQ, hearing loss, and maternal thyroid autoimmunity in the Baltimore Collaborative Perinatal Project

Abstract

Background: Maternal thyroid autoantibodies during pregnancy have been implicated in neurodevelopmental delays, including early childhood cognitive deficits. We evaluated whether maternal autoantibodies to thyroid peroxidase (TPOaabs) during late pregnancy were associated with childhood intelligence quotient (IQ) scores in their offspring and how the children's TPOaab-associated sensorineural hearing loss (hL) might affect the result. Methods: We evaluated banked third-trimester sera corresponding to 1,733 children for whom childhood cognitive test scores and audiology data were available. The mothers and their children participated in the National Institutes of health (NIh)-sponsored collaborative Perinatal Project (cPP) that ran from 1959 to 1974. results: a modest, statistically significant, effect of TPOaabs on cognitive performance observed at 4 y of age lessened in both magnitude and P value by the age of 7 y. children with sensorineural hL (sNhL) had lower IQ scores at both ages. conclusion: Our data suggest that the reported effect of maternal TPOaabs on IQ may involve early developmental delays or transient effects rather than permanent deficits. Reports associating TPOaabs directly with IQ may reflect a portion with unexamined TPOaab-associated sNhL. Whether the TPOaab-associated sNhL is in the neurodevelopmental pathway of later cognitive delays or is independently associated with IQ requires investigation in other studies.

Maternal thyroid disease and its effects on the fetus and perinatal outcomes

“…28 It is not clear why an elevation in thyroid autoantibodies in women who are euthyroid is associated with changes in neurodevelopment. 40 Although age did not differ significantly between negative and positive maternal TPO antibody status in some of these studies, 37,39 and in other studies, they corrected for maternal age, 38 it is important to note that many women with thyroid antibodies also have increased maternal age which itself is a risk factor for adverse outcomes and may confound the findings. 41 In summary, maternal thyroid dysfunction has been shown to be…”

“…There are some data that thyroid autoantibodies may affect neurodevelopmental outcomes, separate from premature delivery effects. 28,[37][38][39][40] Cohort studies have shown increased sensorineural hearing loss and higher risk of ADHD even after correcting for TSH. 37,38 Studies have also shown an increased odds of ASD with positive thyroid autoantibodies with no difference between hypothyroid and euthyroid participants.…”

“…41,54,[59][60][61][62] The mechanism may be that through autoimmunemediated destruction of the thyroid gland, thyroid antibodies can affect the capacity of the thyroid to produce thyroid hormone and thus the thyroid may not be able to keep up with the increased demand needed in pregnancy, thus becoming abnormal later in pregnancy even in initially euthyroid women. 7,40 As it has been shown that autoantibodies increase pregnancy and neonatal risk, it is reasonable to ask if treatment with thyroid replacement would improve outcomes, even in those with normal thyroid function. 41 A small randomized trial showed some benefit of levothyroxine therapy on the rate miscarriage and preterm delivery.…”

Maternal Thyroxine Levels During Pregnancy and Outcomes of Cognitive Development in Children

“…After screening the titles and abstracts, 22 studies were further assessed for eligibility by reading full-text [12][13][14][15][16][17][18][19]. After reviewing full-text, 15 articles were excluded because of not relevant design or lack of usable data [12,[23][24][25][26][27][28][29][30][31][32][33][34][35][36]. Thus, seven prospective cohort studies were finally included into the metaanalysis [13][14][15][16][17][18][19].…”

The Effectiveness of Brain Gym and Brain Training Intervention on Working Memory Performance of Student with Learning Disability

“…What causes learning disabilities?. According to researches there are various factors that cause difficulties in learning including imperfect formation of ears and hearing senses that affect early learning as early as in the womb (Wasserman et al, 2012), imbalance brain chemical caused by the imperfection of neurotransmitter function (Healy, 2004), birth trauma and emotional trauma during developmental process which causes disability learning failure associated with sensory integration and executive functions of the brain (May-Benson et al, 2009), allergies and nutritional aspects that influence the performance of children at school (Phyllis, 2013).…”