Free T4 Levels (free t4 + level)

Distribution by Scientific Domains


Selected Abstracts


Transient hyperthyroidism of hyperemesis gravidarum

BJOG : AN INTERNATIONAL JOURNAL OF OBSTETRICS & GYNAECOLOGY, Issue 6 2002
Jackie Y.L. Tan
Objective To characterise the clinical, biochemical and thyroid antibody profile in women with transient hyperthyroidism of hyperemesis gravidarum. Design Prospective observational study. Setting Hospital inpatient gynaecological ward. Population Women admitted with hyperemesis gravidarum and found to have hyperthyroidism. Methods Fifty-three women were admitted with hyperemesis gravidarum and were found to have hyperthyroidism. Each woman was examined for clinical signs of thyroid disease and underwent investigations including urea, creatinine, electrolytes, liver function test, thyroid antibody profile and serial thyroid function test until normalisation. Main outcome measures Gestation at which thyroid function normalised, clinical and thyroid antibody profile and pregnancy outcome (birthweight, gestation at delivery and Apgar score at 5 minutes). Results Full data were available for 44 women. Free T4 levels normalised by 15 weeks of gestation in the 39 women with transient hyperthyroidism while TSH remained suppressed until 19 weeks of gestation. None of these women were clinically hyperthyroid. Thyroid antibodies were not found in most of them. Median birthweight in the infants of mothers who experienced weight loss of >5% of their pre-pregnancy weight was lower compared with those of women who did not (P= 0.093). Five women were diagnosed with Graves' disease based on clinical features and thyroid antibody profile. Conclusions In transient hyperthyroidism of hyperemesis gravidarum, thyroid function normalises by the middle of the second trimester without anti-thyroid treatment. Clinically overt hyperthyroidism and thyroid antibodies are usually absent. Apart from a non-significant trend towards lower birthweights in the infants of mothers who experienced significant weight loss, pregnancy outcome was generally good. Routine assessment of thyroid function is unnecessary for women with hyperemesis gravidarum in the absence of any clinical features of hyperthyroidism. [source]


Cord blood thyroid-stimulating hormone and free T4 levels in Turkish neonates: Is iodine deficiency still a continuing problem?

PEDIATRICS INTERNATIONAL, Issue 5 2010
Fatih K
Abstract Background:, The objectives of this study were to determine the cord blood thyroid-stimulating hormone (TSH) and free T4 (FT4) levels in Turkish neonates and to determine whether these variables reveal iodine deficiency. Methods:, We collected 818 cords from healthy mothers at parturition and measured levels of FT4 and TSH. We also measured cord blood FT4 and TSH levels in different stages of gestation and gender. We grouped the neonates according to cord serum TSH levels, either being less (Group A) or greater (Group B) than 10 mIU/L. Group A included 589 neonates (300 girls [51%] and 289 boys [49%]) and Group B included 229 neonates (105 girls [45%] and 124 boys [55%]). Results:, The percentage of subjects with cord blood TSH < 10 mIU/L and >10 mIU/L was 72% and 28%, respectively. Although cord TSH levels in Group B were greater than those in Group A (P < 0.001), cord blood FT4 levels in Group B were lower than those in Group A (P < 0.05). There was no difference between both sex in terms of birthweight and maternal age. TSH and FT4 levels did not vary according to neonate sex during gestation, except for from week 37 to 41. TSH levels of male neonates at the 41st week of gestation were higher than those of female neonates (P < 0.05). There were no effects of birthweight on TSH and FT4 levels if the neonate was lighter than 2500 g at birth. TSH levels of male neonates were higher than those of female neonates when their birthweights were <2500 g (P < 0.05). There was no significant difference in TSH levels according to birthweights in male neonates. Conclusion:, Our data provide the normative data for cord blood TSH and FT4 levels in Turkish neonates and show that iodine deficiency is a still a public health problem in Turkey. These measurements can be useful for detection and verification of hypothyroidism in a screening program for congenital hypothyroidism as well as evaluation of the success of the iodination program. [source]


Effects of therapeutic and toxic doses of levamisole on thyroid hormones and some biochemical parameters in sheep

CELL BIOCHEMISTRY AND FUNCTION, Issue 5 2004
Ahmet Atessahin
Abstract This study was carried out to establish the effects of therapeutic and toxic doses of levamisole on thyroid hormone levels and some biochemical parameters in sheep. Twelve Akkaraman ewes were used. Levamisole was given orally at doses of 7.5,mg,kg,1 (group 1) and 40,mg,kg,1 (group 2) to the animals. Blood samples were taken from the jugular vein at 2, 4, 8, 24, 48, 96 and 144,h after the administrations. Serum thyroid hormones and some biochemical parameters were determined on these samples. When compared with the control levels, no significant changes were observed in triiodothyronine (T3) and thyroxin (T4) levels in group 1. Although levamisole was found to increase the levels of total T3, it decreased the levels of total T4 in group 2. On the other hand, free T3 and free T4 levels were not changed in either group. While serum alkaline phosphatase (ALP) activities were decreased, aspartate aminotransferase (AST), alanine aminotransferase (ALT), lactate dehydrogenase (LDH) and creatinine kinase (CK) activities were increased significantly by levamisole. However, it increased the serum albumin and cholesterol levels, but decreased the inorganic phosphate levels in groups 1 and 2. On the other hand, when compared with the control levels, no significant changes were detected in serum sodium, potassium and calcium levels. In conclusion, therapeutic and toxic doses of levamisole were determined to affect thyroid metabolism and some biochemical parameters in sheep. Copyright © 2004 John Wiley & Sons, Ltd. [source]


Ethnic differences in TSH but not in free T4 concentrations or TPO antibodies during pregnancy

CLINICAL ENDOCRINOLOGY, Issue 6 2007
N. Benhadi
Summary Objective, To describe the TSH, free T4 and thyroid peroxidase antibody (TPO-Ab) concentrations during pregnancy among four ethnic groups and to determine reference values for these parameters during normal pregnancy. Methods, Cross-sectional study of a cohort of 3270 pregnant women living in the city of Amsterdam. Blood samples were drawn at first booking in the first or second trimester. TSH, free T4 and TPO-Ab concentrations were determined. Four ethnic groups were studied: Dutch, Surinam, Turkish and Moroccan. Results, Plasma TSH increased and free T4 decreased from the first to the second trimester of pregnancy for all the ethnic groups. Ethnic differences were observed in TSH concentrations, with Dutch females having the highest TSH levels compared to the other three ethnic groups. The median TSH difference was 0·16 mU/l between the Dutch and Moroccan women, 0·15 mU/l between the Dutch and Surinam women and 0·10 mU/l between the Dutch and Turkish women. These could not be explained by differences in age, parity and current smoking status. No differences were seen in free T4 concentrations between the four ethnic groups. The prevalence of TPO-Ab was comparable across the ethnic groups (about 6% in each); the concentration of TPO-Ab was also comparable among the ethnic groups. The Dutch women had a higher lower-limit (2·5 percentile) of the TSH reference range than the Surinam, Turkish and Moroccan women, ranging from 0·14 mU/l for the Surinam and Moroccan to 0·27 mU/l for the Dutch women. Conclusion, The increase in TSH and decrease in free T4 values during pregnancy correspond to previous reported studies. Pregnant Dutch women had consistently higher TSH values than the ethnic group, but corresponding free T4 levels and TPO-Ab did not differ between these ethnic groups. [source]