Antenatal Thyroid Screening and Childhood Cognitive Function

Queen Mary, University of London, Londinium, England, United Kingdom
New England Journal of Medicine (Impact Factor: 55.87). 02/2012; 366(6):493-501. DOI: 10.1056/NEJMoa1106104
Source: PubMed

ABSTRACT Children born to women with low thyroid hormone levels have been reported to have decreased cognitive function.
We conducted a randomized trial in which pregnant women at a gestation of 15 weeks 6 days or less provided blood samples for measurement of thyrotropin and free thyroxine (T(4)). Women were assigned to a screening group (in which measurements were obtained immediately) or a control group (in which serum was stored and measurements were obtained shortly after delivery). Thyrotropin levels above the 97.5th percentile, free T(4) levels below the 2.5th percentile, or both were considered a positive screening result. Women with positive findings in the screening group were assigned to 150 μg of levothyroxine per day. The primary outcome was IQ at 3 years of age in children of women with positive results, as measured by psychologists who were unaware of the group assignments.
Of 21,846 women who provided blood samples (at a median gestational age of 12 weeks 3 days), 390 women in the screening group and 404 in the control group tested positive. The median gestational age at the start of levothyroxine treatment was 13 weeks 3 days; treatment was adjusted as needed to achieve a target thyrotropin level of 0.1 to 1.0 mIU per liter. Among the children of women with positive results, the mean IQ scores were 99.2 and 100.0 in the screening and control groups, respectively (difference, 0.8; 95% confidence interval [CI], -1.1 to 2.6; P=0.40 by intention-to-treat analysis); the proportions of children with an IQ of less than 85 were 12.1% in the screening group and 14.1% in the control group (difference, 2.1 percentage points; 95% CI, -2.6 to 6.7; P=0.39). An on-treatment analysis showed similar results.
Antenatal screening (at a median gestational age of 12 weeks 3 days) and maternal treatment for hypothyroidism did not result in improved cognitive function in children at 3 years of age. (Funded by the Wellcome Trust UK and Compagnia di San Paulo, Turin; Current Controlled Trials number, ISRCTN46178175.).

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    • "In addition, Chevrier et al. [16] found no association between maternal hypothyroxinemia and psychomotor development of the offspring having analyzed the thyroid function of 287 pregnant women and having followed-up the children until 5 years of age. In 2012, Lazarus et al. [17] reported a randomized study without finding any cognitive improvement in children born to mothers who received levothyroxine for treating hypothyroidism or transient maternal hypothyroxinemia during pregnancy. These authors assessed thyroid function at 12 weeks of pregnancy and mothers were randomized into two groups. "
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    ABSTRACT: Proper maternal thyroid function is known to be essential for neural differentiation and migration in the fetus during the first half of pregnancy. The objectives of this study were to assess the relationship between thyroxin levels, in pregnant women with no thyroid disease and the intellectual development of their offspring in a non-iodine-deficient area, and to know specifically whether or not isolated hypothyroxinemia during pregnancy was associated with a lower intelligence in the offspring. Previously we had publicated values TSH, FT4, free T3 (FT3), anti-thyroid peroxidase antibodies (TPO Abs) and urinary iodine concentration (UIC) in 1322 pregnant women in our hospital area. Now we presented results of intelligence quotient in children born from these pregnancies. We assessed 455 children at one year of age using Brunet-Lezine scale. Of these, 289 children were evaluated again at 6-8 years of age using the WISC-IV. From the total group of children recruited, we established as control subgroup, children born of rigorously normal pregnancies (women with UIC>150μg/L, FT4>10th percentile and TPO-Ab negative in both trimesters). The remaining children were divided into two subgroups: those born to mothers with FT4 below the 10th percentile and the rest. No correlation was found between FT4 maternal levels, in either of trimesters studied, and the intellectual scores of offspring. No differences were found in intellectual scores comparing children born to mothers with hypothyroxinemia and those whose mothers were euthyroxinemic in both trimesters, or with the control subgroup. As conclusions we did not find any association between the levels of maternal FT4 during pregnancy and the subsequent intellectual development the offspring from these pregnancies. We attribute this result to the fact that all the pregnant women included had normal thyroid function. Copyright © 2015 Elsevier GmbH. All rights reserved.
    Journal of Trace Elements in Medicine and Biology 02/2015; 31. DOI:10.1016/j.jtemb.2015.02.004 · 2.37 Impact Factor
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    • "Since the ATA supports the use of assay-specific, trimester specific reference intervals to define thyroid dysfunction during pregnancy [8], according to the standard of the National Academy of Clinical Biochemistry (NACB) [10], we formulated independent trimester-specific normal reference intervals for thyroid function, and all pregnant women were diagnosed according to the reference values. In our study, the upper limit of TSH for diagnosis of hypothyroidism was 3.47 mU/L in the first trimester and 3.81 mlU/L in the second trimester, which was similar to the cutoff used by Lazarus et al. [20]. According to our results, 100% (2 of 2) of women with overt hypothyroidism and 66.7% (4 of 6) of women with overt hyperthyroidism would have been identified by high risk screening strategy in the first trimester. "
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    ABSTRACT: Thyroid dysfunction during pregnancy is associated with multiple adverse outcomes, but whether all women should be screened for thyroid disorders during pregnancy remains controversial.
    PLoS ONE 06/2014; 9(6):e99611. DOI:10.1371/journal.pone.0099611 · 3.23 Impact Factor
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    • "Lazarus et al evaluated 21846 pregnant women and their children in their large-scale randomized studies.18 It showed that significant increase did not occur in the cognitive functions in three years of age with the treatment. "
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    ABSTRACT: Objective: Primary objective of our study was to evaluate the efficiency of detailed medical history and thyroid examination of the pregnant women presenting to our clinic from Rize province and nearby which was an endemic goiter region. It was aimed to investigate the frequency of thyroid diseases, pregnancy outcomes and the efficiency of screening with thyroid function tests during the first trimester of pregnancy as secondary endpoint. Methodology : A prospective clinical study was conducted with 998 pregnant women between the ages of 17-48 years. In the first step of our study, a detailed medical history was obtained and a detailed thyroid gland examination was performed in all the patients (n=998). In the patients diagnosed with thyroid disease or considered to have thyroid disease with these results (n=107), thyroid diseases were evaluated with thyroid function tests and imagining methods. Analyses of socio-demographic data and nutrition were also made. In the second step, thyroid stimulating hormone (TSH), free T3 and free T4 tests were performed in the first antenatal examination of the pregnant cases considered not to have thyroid disease after medical history and examination (n=891). Parameters of thyroid peroxidase antibodies (TPOAb), thyroglobulin antibodies (TgAb) and TSH receptor auto antibodies (TRAb) were investigated in the cases whose TSH, sT3 and sT4 levels were different than the reference values after examination of the endocrinologist. Thyroid ultrasonography was performed. Urinary iodine levels in 24 hour urine were investigated. Results: During pregnancy, the incidence of hyperthyroidism and hypothyroidism in the whole study group were 2.8% (28/998) and 4.3% (43/998), respectively, 6.7% of the patients (67/998) had a diagnosis of thyroid disease before pregnancy. Hyperthyroidism and hypothyroidism depending on the TSH screening results were 1.9% (17/891) and 1.1% (10/891) respectively and the incidence of overt hyperthyroidism and overt hypothyroidism were 0.2% (2/891) and 0.2% (2/891) in the pregnant cases considered not to have thyroid disease with medical history and examination. Conclusion: Detailed medical history and family history obtained during the first trimester of pregnancy helped us to identify 6.7% of thyroid diseases among the pregnant women. This result effectively emphasizes the importance of detailed first prenatal examination regarding the thyroid.
    Pakistan Journal of Medical Sciences Online 09/2013; 29(5):1187-92. DOI:10.12669/pjms.295.3647 · 0.23 Impact Factor
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