Controlled Antenatal Thyroid Screening II: effect of treating maternal sub-optimal thyroid function on child cognition.

Controlled Antenatal Thyroid Screening II: effect of treating maternal sub-optimal thyroid function on child cognition.

J Clin Endocrinol Metab. 2018 Jan 15;:

Authors: Hales C, Taylor PN, Channon S, Paradice R, McEwan K, Zhang L, Gyedu M, Bakhsh A, Okosieme O, Muller I, Draman MS, Gregory JW, Dayan C, Lazarus JH, Rees DA, Ludgate M

Abstract
Context & Objective: The Controlled Antenatal Thyroid Screening (CATS) study investigated treatment for suboptimal gestational thyroid function (SGTF) on childhood cognition and found no difference in IQ at 3 years between children of treated and untreated SGTF mothers. We have measured IQ in the same children at age 9.5-years and included children from normal-GTF mothers.
Design, Setting & Participants: One examiner, blinded to participant group, assessed children's IQ (WISC-IV), long-term memory and motor function (NEPSY-II) from children of 119 treated and 98 untreated SGTF mothers plus children of 232 mothers with normal-GTF. Logistic regression explored the odds and percentages of IQ<85 in the groups.
Results: There was no difference in IQ<85 between children of mothers with normal-GTF and combined SGTF i.e. treated and untreated (fully adjusted OR=1.15 (95% CI 0.52, 2.51) p=0.731). Furthermore, there was no significant effect of treatment (untreated OR=1.33 (95% CI 0.53, 3.34), treated OR=0.75 (95% CI 0.27, 2.06) p=0.576). IQ< 85 was 6.03% in normal-GTF, 7.56% in treated and 11.22% in untreated groups. Analyses accounting for treated-SGTF women with FT4 >97.5th centile of the entire CATS-I cohort revealed no significant effect on child's IQ<85 in CATS-II. IQ at age 3 predicted IQ at age 9.5 (p<0.0001) and accounted for 45% of the variation.
Conclusions: Maternal thyroxine during pregnancy did not improve child cognition at age 9.5 years. Our findings confirmed CATS-I and suggest that the lack of treatment effect may be due to the similar proportion of IQ<85 in children of women with normal-GTF and SGTF.

PMID: 29346569 [PubMed - as supplied by publisher]

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