Effects of maternal postpartum thyroiditis on thyroid function, intelligence quotient and cognitive development of their offspring

The effect of thyroid hormones on all stages of the development of central nervous system has been documented in different studies. Postpartum thyroiditis [PPT] is associated with high titers of TPO-Ab during pregnancy. Thyroid autoimmunity in pregnancy results in reduction of serum free thyroxin level, even in the presence of normal thyroid function. This study was conducted to evaluate the effect of PPT on the thyroid function and cognitive development of the offspring. Materials and Methods: In this prospective cohort study, conducted between December 2007 and March 2008, children born to mothers who had developed postpartum thyroiditis after delivery and those mothers who had not, were included in this study. Blood and urine samples were obtained from all children and blood samples were drawn from their mothers. All children underwent 7 cognitive tests in a clinical psychology laboratory. Results: We enrolled 124 children for the study, 55 cases [children of mothers with PPT] and 69 controls [children of mothers without PPT]. Average age of cases was 9.5 +/- 1.4 and in controls was 9.4 +/- 0.1 [P=0.2]. No difference was noted between the two groups for baseline characteristics which might have affected their neurodevelopment. Mean scores for total IQ, performance IQ, and verbal IQ in cases and controls were as follows: 115 +/- 10 vs. 116 +/- 12, 113 +/- 11 vs. 116 +/- 12, and 113 +/- 12 vs. 113 +/- 13, respectively [P=0.5]. There was no difference between the results of the other tests [CPT, WCST, PRM Test, SWM Test, MFVP Test, SOC] in the two groups. No difference was noted between the thyroid function of the two groups. Conclusion: Prevalence of goiter, thyroid function, cognitive development, and intelligence quotient of children born to mothers who later develop postpartum thyroiditis are similar to those of normal children. Postpartum thyroiditis in mother is not a threat for the newborn