Pediatric reference values of TSH should be personalized according to BMI and ethnicity.

OBJECTIVE: The need for personalization of the reference values of thyroid function tests has been previously suggested. We aimed at determining TSH reference values in a large cohort of children according to age, sex, BMI, and ethnicity. DESIGN: A population-based cohort study. METHODS: The study cohort included 75 549 healthy children aged 5-18 years. Data analyzed included age, gender, TSH, FT4 levels, BMI and ethnicity. Multivariate logistic regression analysis examined the associations between the study parameters. RESULTS: TSH in the Jewish population is lower than in the non-Jewish population (median: 2.1 IU/L (IQR: 1.5) vs 2.2 IU/L (IQR: 1.5), P < 0.0001). TSH is significantly affected by BMI for children defined as underweight, normal weight, overweight or obese, levels increased as weight diverged from the normal range (median levels: 2.1 IU/L (IQR: 1.4), 2.0 IU/L (IQR: 1.3), 2.1 IU/L (IQR: 1.4), 2.4 (IQR: 1.5), respectively, P < 0.001). The 2.5 percentile is affected by gender and BMI (P < 0.02 and P < 0.001, respectively), while the 97.5 percentile is affected by ethnic origin and BMI (P < 0.001 for both). New TSH reference intervals (RI) adjusted according to BMI and ethnicity are suggested. Comparison of the old and new RI demonstrate the significance of RI personalization: 25.1% of the children with TSH levels above the old RI are within the new RI, while 2.3% of the children who were in the old RI are below the new RI. CONCLUSIONS: TSH reference values in children are affected by BMI and ethnicity. Reference values should be individualized accordingly to improve future clinical decision-making and treatment.

The association between maternal serum first trimester free ßhCG, second trimester intact hCG levels and foetal growth restriction and preeclampsia.

The purpose of this study was to analyse the association between free beta hCG (fßhCG) increased levels and pregnancy complications (PC), foetal growth restriction (FGR) and preeclampsia (PE). This connection was evaluated in two stages (i) investigating the association between those PC with first trimester fßhCG and second trimester intact hCG (ihCG), and (ii) studying the association between these two analytes in the same pregnancy. This was a retrospective study in two settings: medical centre that provided data on fßhCG and ihCG levels in pregnancies with FGR and PE, and central laboratory that provided fßhCG and ihCG levels that were compared in the same pregnancy. No association was found between those PC and the hCG analytes, except for elevated ihCG levels and FGR. Elevated fßhCG (>3.00 MoM) was found in 570/16,849 (3.4%) women. However, only 14% of whom had elevated second trimester ihCG. A positive correlation was found between the magnitude of first trimester fßhCG levels and the percentage of women who had elevated second trimester ihCG. This association was determined by the magnitude of the elevation of fßhCG levels. Impact statement What is already known on this subject: The two analytes, first trimester fßhCG and second trimester ihCG, are independently produced and parameters of the biochemical screening during pregnancy. What the results of this study add: Referring to 3.00 MoM as cut-off levels, most pregnancies with elevated levels of first trimester fßhCG will have normal ihCG second trimester levels. What the implications are of these findings for clinical practice and/or further research: The risk of developing pregnancy complications, FGR and PE should be associated with second trimester ihCG levels. About 3.5% of women had high fßhCG levels during the first trimester. However, only 14% also had increased ihCG levels, defined as >3.00 MoM; additional studies are needed to explore the association between increased first trimester fßhCG levels and the risk of developing pregnancy complications, independent of ihCG levels in the second trimester.

Is the ratio of maternal serum to amniotic fluid AFP superior to serum levels as a predictor of pregnancy complications?

PURPOSE: The use of maternal serum alpha fetoprotein (MSAFP) levels as a predictor of pregnancy complications (PC) is well established. We hypothesized that the ratio between the MSAFP/AFAFP levels (RATIO) will more accurately predict PC than MSAFP levels alone. METHODS: Women who had a MSAFP test followed by amniocentesis were divided into two groups: those who had PC comprised the study group and those who had an uneventful pregnancy served as the control group. Data regarding pregnancy and delivery course were collected. The RATIO between the study and the control groups was compared. RESULTS: 166 women were included in the study, of which 24 had PC. A significant correlation was found between the RATIO and intrauterine growth restriction (IUGR) and week of delivery. Six pregnancies had elevated MSAFP levels; two with RATIO below 2 had uneventful pregnancies. Among the other four pregnancies with RATIO above two, one had IUGR and the other, placental abruption. CONCLUSION: Our data suggest that the RATIO might serve as a predictor of IUGR and week of delivery. Although the number of patients in the current study was relatively small, the novelty of the proposed simple marker implies that a larger scale study is warranted. Such studies may confirm this finding and a possible advantage of using this RATIO instead of or in addition to MSAFP values for better prediction of pregnancies at risk for PC.