Cord Thyroid Stimulating Hormone Research Articles

Establishing Umbilical Cord Thyroid-stimulating Hormone in Neonates at a Tertiary Care Teaching Hospital for Screening Congenital Hypothyroidism

Establishing Umbilical Cord Thyroid-stimulating Hormone in Neonates at a Tertiary Care Teaching Hospital for Screening Congenital Hypothyroidism

Congenital hypothyroidism screening with umbilical cord blood thyroid-stimulating hormone at birth and peripheral venous blood thyroid-stimulating hormone after 72 h at a hospital in suburban area of Chhattisgarh

Background: Primary congenital hypothyroidism (CH) is the most common cause of hypothyroidism in infancy and early childhood. Neonatal screening programs for the detection of CH in the neonatal period are widespread and in most screening programs, blood samples are collected at 5–6 days age. Objective: The objective of the study was to obtain cord blood (CB) samples at birth and the peripheral venous blood sample of thyroid-stimulating hormone (TSH) at 72 h. Materials and Methods: This cross-sectional observational study was done at a tertiary suburban center and a total of 1470 newborn delivered was enrolled after satisfying the inclusion criteria. Umbilical CB TSH sample was taken at birth and peripheral venous sample for TSH was taken at 72 h. TSH values more than 20 ?IU/mL, in both groups, were taken as an upper limit of normal. Results: Out of 1470 samples collected, among those with umbilical cord sample, 31 (2%) had a value >20 ?IU/mL, while only one baby had a value of TSH >20 ?IU/mL at 72 h of life and was diagnosed as CH. Conclusion: The incidence of CH is 1 out of 1470 neonates. Female gender, maternal age, and lower socioeconomic status of parents have a significant impact on umbilical cord TSH Levels.

Compliance of diagnosis and early management of congenital hypothyroidism

Objective: This study aimed to estimate the prevalence and the compliance of early diagnosis and early management of congenital hypothyroidism (CH). Materials and Methods: This retrospective cohort study gathered data from all infants born over 10 years from January 2007 to December 2016. All children diagnosed with CH as per standard definition of cord and follow-up thyroid-stimulating hormone (TSH) levels were analyzed to calculate the prevalence and the compliance rates to early treatment goal and time normalization of TSH. These children were evaluated for neurodevelopment outcomes. Results: 31,311 newborns screened for CH with a prevalence over 10 years of 1:3085 per live births. Among the 11 cases, five were found to have thyroid dysgenesis (1:6200), 5 thyroid dyshormonogenesis (1:6200), and only one case of generalized resistance to thyroid hormone (1:31000). The compliance with an early diagnosis within the first 2 weeks was 100%, and compliance with the initial treatment goal was 40%. Normalization was achieved in all cases within 16 weeks; however, all had normal hearing, vision, and development at their current age. Conclusion: The prevalence of CH in this single tertiary care center is similar to national and international data. Dyshormonogenesis has a higher prevalence than global data. Moreover, compliance with early diagnosis is excellent due to the strict adherent cord TSH protocol. The compliance with the initial treatment goal in our center is comparable with international data. However, large population-based studies are needed to establish a benchmark on such compliance rates. The long-term hearing, vision, and development milestone assessments of diagnosed cases were age appropriate.

Association of Cord Blood Thyroid-Stimulating Hormone Levels with Maternal, Delivery and Infant Factors

This study examined maternal, delivery and infant factors associated with cord thyroid-stimulating hormone (TSH) concentrations in an Asian population. The Growing Up in Singapore Towards healthy Outcomes (GUSTO) study is a mother-offspring birth cohort from 2 major hospitals in Singapore. Cord serum TSH was measured using the Abbott ARCHITECT TSH Chemiluminescent Microparticle Immunoassay and the ADVIA Centaur TSH-3 Immunoassay. After excluding infants with a maternal history of thyroid disease, screening cord TSH results from 604 infants were available for multivariable regression analysis in relation to the factors of interest. Babies born by vaginal delivery had significantly higher cord serum TSH concentrations than babies born by caesarean section. Cord serum TSH concentrations differed significantly by measurement method. There was no association of cord TSH concentrations with ethnicity, sex, birth weight, gestational age, maternal body mass index, gestational weight gain, gestational diabetes mellitus status and other maternal, delivery and infant factors studied. Interpretation of cord serum TSH results may need to take into account mode of delivery and measurement method.

Maternal urinary bisphenol A concentration and thyroid hormone levels of Chinese mothers and newborns by maternal body mass index.

Animal studies indicated that bisphenol A (BPA) exposure during pregnancy may disrupt thyroid function which is critical for fetal development. However, few epidemiological studies have examined this topic and the results were inconsistent. We aimed to evaluate whether prenatal BPA exposure is associated with thyroid hormone levels in Chinese mothers and newborns with stratification by maternal body mass index (BMI). BPA concentration were measured in urine samples collected from 555 women at late pregnancy. Maternal serum free thyroxin (FT4), thyroid-stimulating hormone (TSH) and thyroid peroxidase antibody (TPO-Ab) concentrations at the third trimester were abstracted from medical records. Cord serum-free triiodothyronine (FT3), FT4, TSH, and TPO-Ab levels were measured in 398 newborns. Prenatal urinary BPA was detected in 98.5% of mothers with a geometric mean of 1.32ng/mL (95% CI 1.17-1.49ng/mL). With each 10-fold increase in BPA concentrations, maternal log10_(TSH) mIU/L was 0.10 lowered (95% CI - 0.20, - 0.005, p < 0.05) among pre-pregnancy BMI>23kg/m2, with adjustment for maternal age, maternal education, gestation diabetes mellitus (GDM), husband smoking during pregnancy, parity, and gestational age at thyroid parameters measured, but no association was observed in pre-pregnancy BMI < 18.5, or 18.5-22.9kg/m2 stratum. No BPA-associated changes were observed in maternal FT4 level or odds of positive TPO-Ab in all BMI stratum. Also, no associations were observed between prenatal urinary BPA concentration and cord serum FT4, FT3, TSH levels, and odds of positive TPO-Ab in both male and female newborns among pre-pregnancy BMI < 18.5, 18.5-22.9 or>23kg/m2 stratum. In this study, prenatal urinary BPA concentration was associated with lower maternal TSH among women with overweight, but not associated with other maternal thyroid parameters or cord serum thyroid parameters across maternal BMI categories. More research on pregnant women and newborns cohort with BPA exposure are warranted.

Evaluation of thyroid function in a sample of newborns through different modes of delivery

Background and objective: Congenital hypothyroidism is the most common preventable cause of mental retardation detected during early childhood. Its early diagnosis is crucial for a better outcome. Many factors are contributed to this problem including maternal, fetal and others. This study aimed to assess thyroid hormone status in relation to certain obstetrical especially mode of delivery and neonatal factors Methods: A descriptive cross-sectional study conducted in postnatal care and delivery room (operative and vaginal) of Maternity teaching hospital in Erbil city. Ninety-two babies were included and subdivided into three groups according to their route of delivery. A thyroid stimulating hormone cut off value of 10 was selected as the upper normal level for the purpose of the study. Results: A significant proportion of babies with cord thyroid stimulating hormone concentration more than 10 mIU/L (25 out of 92) were noticed, and this is near to many previous studies used the same cut off value. Mean of This hormone is relatively increased among newborns of the elective cesarean section while maternal total triiodothyronine and total thyroxine were higher within the elective group. Prenatal evidence of placental calcification and first born babies were associated with higher thyroid stimulating hormone levels. Conclusion: Emergency cesarean section is less likely to be associated with elevated cord blood thyroid stimulating hormone level compared to other routes of delivery/but this is not confirmatory and recall test is recommended to exclude hypothyroidism.

Gestational Perfluoroalkyl Concentrations and Thyroid Hormone Levels in Faroese Pregnant Women and Neonates: A Prospective Cohort Study

Background: Exposure to perfluoroalkyl substances (PFASs) may disrupt maternal and neonatal endocrine function. Adequate thyroid hormone (TH) levels during pregnancy are essential for fetal and early childhood development.Objective: To assess the relationship between gestational PFAS exposures and maternal and cord TH levels.Methods: Data was collected from a cohort of 182 mother-child pairs from 1994-1995 in the Faroe Islands. The concentrations of 17 PFASs, including perfluorooctane sulfonate (PFOS) and perfluorooctanoic acid (PFOA) were measured in maternal serum. Maternal and cord serum were measured for THs such as thyroid stimulating hormone (TSH), free thyroxine (FT4), thyroxine (T4), free triiodothyronine (FT3), free triiodothyronine resin uptake (T3RU), and free T4 index (FTI). We examined relationships between PFAS concentrations and TH levels using multivariable regression models and effect measure modification in sex-stratified analyses.Results: PFAS concentrations were mostly positively associated with both maternal and fetal TSH. PFOS and PFOA had the strongest estimates; doubling PFOS and PFOA concentrations were associated with 49% (95% CI: 18, 87%) and 33% (95% CI: 11, 59%) increase in cord TSH concentrations respectively. Perfluorooctanesulfonamide (PFOSA) was negatively associated with maternal FT4 and T3RU but positively associated with cord T4 and FTI levels. In mothers carrying female fetuses, doubling PFOS concentrations was associated with a 54% (95% CI: 14, 109%) increase in maternal TSH, but not in mothers bearing male neonates (-5%; 95% CI: -27, 24%). We did not observe consistent patterns for sex-stratified associations between gestational PFAS concentrations and cord TH levels.Conclusions: Prenatal exposure to several PFASs during pregnancy, such as PFOS and PFOA, is associated with increases in infant TSH levels. PFOS may also affect maternal TSH levels depending on the fetus&amp;#8217;s sex, the implications of which are still to be understood.

Exposure to phthalates during pregnancy and thyroid hormones in pregnant women and newborns

Introduction: Phthalates are endocrine disrupting chemicals found in many consumer products. Prior evidence suggests that some phthalates may disrupt thyroid function, but the effect of phthalates on thyroid hormones in pregnant women and neonates has not been thoroughly investigated. Methods: We measured nine phthalate metabolites representing exposure to six parent phthalate diesters in urine collected at ~16 and 26 weeks gestation in a prospective pregnancy and birth cohort. We calculated the mean of 16 and 26 week metabolite concentrations and created exposure quartiles. We measured thyroid stimulating hormone (TSH), free and total thyroxine (FT4, TT4), and triiodothyronine (FT3, TT3) concentrations in maternal serum at ~16 weeks (n=184) and in cord serum (n=275). We estimated the associations of phthalates with maternal or cord thyroid hormones by multivariable linear regression. Results: Mothers in the 4th quartile of urinary monoethyl phthalate (MEP) had 0.05 ng/dL lower FT4 (95%CI -0.09, -0.01) compared to those in the 1st quartile (p-trend=0.02). Cord TSH was 19.8% lower among infants born to women in the 4th quartile of monobenzyl phthalate (MBzP) (95%CI: -34.1, -2.3), compared to those in the 1st quartile (p-trend 0.03). Infants born to mothers in the 4th quartile of di(2-ethylhexyl) phthalate (DEHP) metabolites had decreased cord FT3 [-0.09 pg/mL (95%CI: -0.19, 0.01); p-trend=0.04] versus those in the 1st quartile. We observed marginally significant inverse trends of both MEP (p-trend=0.06) and monoisobutyl phthalate (MiBP) (p-trend=0.06) with cord TT4. Conclusions: In this cohort, maternal urinary MEP was inversely associated with maternal FT4. Maternal urinary concentrations of MBzP, DEHP metabolites, MEP, and MiBP were inversely associated with cord thyroid hormones. These results suggest that maternal exposure to phthalates during pregnancy may disrupt maternal and cord thyroid hormones necessary for normal growth and neurodevelopment.

Management of Neonates Born to Mothers With Graves' Disease.

Neonates born to mothers with Graves' disease are at risk for significant morbidity and mortality and need to be appropriately identified and managed. Because no consensus guidelines regarding the treatment of these newborns exist, we sought to generate a literature-based management algorithm. The suggestions include the following: (1) Base initial risk assessment on maternal thyroid stimulating hormone (TSH) receptor antibodies. If levels are negative, no specific neonatal follow-up is necessary; if unavailable or positive, regard the newborn as "at risk" for the development of hyperthyroidism. (2) Determine levels of TSH-receptor antibodies in cord blood, or as soon as possible thereafter, so that newborns with negative antibodies can be discharged from follow-up. (3) Measurement of cord TSH and fT4 levels is not indicated. (4) Perform fT4 and TSH levels at day 3 to 5 of life, repeat at day 10 to 14 of life and follow clinically until 2 to 3 months of life. (5) Use the same testing schedule in neonates born to mothers with treated or untreated Graves' disease. (6) When warranted, use methimazole (MMI) as the treatment of choice; β-blockers can be added for sympathetic hyperactivity. In refractory cases, potassium iodide may be used in conjunction with MMI. The need for treatment of asymptomatic infants with biochemical hyperthyroidism is uncertain. (7) Assess the MMI-treated newborn on a weekly basis until stable, then every 1 to 2 weeks, with a decrease of MMI (and other medications) as tolerated. MMI treatment duration is most commonly 1 to 2 months. (8) Be cognizant that central or primary hypothyroidism can occur in these newborns.

Gestational urinary bisphenol A and maternal and newborn thyroid hormone concentrations: The HOME Study

Bisphenol A (BPA), an endocrine disruptor used in consumer products, may perturb thyroid function. Prenatal BPA exposure may have sex-specific effects on thyroid hormones (THs). Our objectives were to investigate whether maternal urinary BPA concentrations during pregnancy were associated with THs in maternal or cord serum, and whether these associations differed by newborn sex or maternal iodine status. We measured urinary BPA concentrations at 16 and 26 weeks gestation among pregnant women in the HOME Study (2003–2006, Cincinnati, Ohio). Thyroid stimulating hormone (TSH) and free and total thyroxine (T4) and triiodothyronine (T3) were measured in maternal serum at 16 weeks (n=181) and cord serum at delivery (n=249). Associations between BPA concentrations and maternal or cord serum TH levels were estimated by multivariable linear regression. Mean maternal urinary BPA was not associated with cord THs in all newborns, but a 10-fold increase in mean BPA was associated with lower cord TSH in girls (percent change=−36.0%; 95% confidence interval (CI): −58.4, −1.7%), but not boys (7.8%; 95% CI: −28.5, 62.7%; p-for-effect modification=0.09). We observed no significant associations between 16-week BPA and THs in maternal or cord serum, but 26-week maternal BPA was inversely associated with TSH in girls (−42.9%; 95% CI: −59.9, −18.5%), but not boys (7.6%; 95% CI: −17.3, 40.2%; p-for-effect modification=0.005) at birth. The inverse BPA–TSH relation among girls was stronger, but less precise, among iodine deficient versus sufficient mothers. Prenatal BPA exposure may reduce TSH among newborn girls, particularly when exposure occurs later in gestation.

Maternal Urinary Bisphenol a during Pregnancy and Maternal and Neonatal Thyroid Hormone Concentrations

Bisphenol A (BPA) is an endocrine disruptor present in many consumer products. Experimental and epidemiologic evidence suggest that BPA disrupts thyroid function. The only prior epidemiologic study of prenatal BPA exposure reported sex-specific effects on thyroid hormones (THs). We examined associations between BPA and THs using multivariable linear regression in the Health Outcomes and Measures of the Environment Study (2003- 2006, Cincinnati, Ohio), a prospective birth cohort. Maternal urinary BPA concentration was measured at approximately 16 and 26 weeks gestation. Free and total thyroxine (T4) and thyroid stimulating hormone (TSH) concentrations were measured in maternal serum at approximately 16 weeks (n=185) and in cord serum (n=252). Separate models were built for a) 16 weeks, b) 26 weeks, and c) 16 and 26 weeks average urinary BPA. We found no associations between 16-week BPA concentration and maternal THs, and between any of the BPA measurements and cord T4. In contrast, each 10-fold increase in average maternal urinary BPA was associated with decreased cord TSH in female newborns (percent change=-31%; 95% confidence interval (CI):-49, -8%) but not males (3%; 95% CI:-26, 42%; p for effect modification=0.04). The 16-week BPA concentration was not associated with TSH (females:-7%; 95% CI:-32, 28%; males:-2%; 95% CI:-33, 42%; p for effect modification=0.87). In contrast, 26-week maternal urinary BPA was associated with reduced TSH for females (-43%; 95% CI:-60, -18%) but not males (-1%; 95% CI:-20, 24%; p for effect modification=0.01). We did not observe associations between BPA and maternal THs during pregnancy or newborn T4. In contrast with one prior study reporting reduced TSH among male newborns only, our findings suggest that prenatal BPA exposure may reduce TSH among female newborns. Consistent with the prior study, maternal BPA exposure later in pregnancy may have greater influence on newborn TSH than in early pregnancy.

Profile of umbilical cord blood TSH ,T4 and influence of perinatal factors on thyroid functions in Newborns

Background: Congenital Hypothyroidism, if not treated well in time, may be disastrous for growth and development of child ,therefore early detection of congenital hypothyroidism is important, either by TSH or T4, or both by newborn screening . Influence of several perinatal factors have to be considered while interpreting values of thyroid functions in newborns. The present study is to determine Umbilical cord blood TSH and T4 profile in Newborns and to study influence of Perinatal factors on Umbilical cord blood TSH and T4 . Methods: Umbilical cord blood samples were collected for assessment of TSH and T4 in 830 newborns. The influence of Perinatal factors such as gestational age ,weight, sex, mode of delivery, Ecclampsia, Ante partum haemorrhage , Birth Asphyxia ,Premature rupture of membranes and maternal HIV status on the newborns TSH ,T4 were analyzed . Results: Mean TSH and T4 levels between Pre term and Term and between Term and Post term was statistically significant .Whereas, only T4 level between Preterm and Post term ,was statistically significant . Mean TSH levels, when compared in babies with & without severe birth asphyxia was also statistically significant . Other perinatal factors did not affect cord TSH and T4 levels ,as it was not statistically significant . Conclusion: Perinatal factors have influence over values of Cord blood TSH and T4 levels and a caution in their interpretation should be considered . Key words: TSH (Thyroid stimulating hormone), CH (Congenital Hypothyroidism), APH (Ante Partum Hemorrhage).

New-born screening for congenital hypothyroidism in Manipur by measurement of umbilical cord thyroid stimulating hormone: A hospital based study

Objective: The objective of this study was to determine the incidence of congenital hypothyroidism (CH) in neonates by measuring umbilical cord thyroid stimulating hormone (TSH), born in a Teaching Hospital in Manipur. Materials and Methods: The study was based on the findings from cord blood samples collected from 1,000 babies born to mothers having no systemic (especially thyroid disorders) and obstetrical complications in the last 2 years. Estimation of serum TSH level was carried out by enzyme-linked immunosorbent assay method using Eliscan TM (Diagnova) kit manufactured by Ranbaxy Fine Chemicals Ltd. (RFCL) India in the Department of Physiology, Regional Institute of Medical Sciences, Imphal. Results: The mean, median and standard deviation for the TSH values of the samples were 8.833 mIU/L, 6.824 mIU/L and 7.059 mIU/L respectively. Nearly, 29.3% of the babies had TSH greater than 10 mIU/L. One baby was found to be having CH out of the 1,000 screened. Conclusion: CH represents one of the most common preventable causes of mental retardation. The finding of 1 case of CH out of 1,000 new-borns screened indicates that incidence is high in this state. Screening of all new-borns in the future is highly recommended.

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

The objectives of this study were to determine the cord blood thyroid-stimulating hormone (TSH) and free T(4) (FT(4) ) levels in Turkish neonates and to determine whether these variables reveal iodine deficiency. We collected 818 cords from healthy mothers at parturition and measured levels of FT(4) and TSH. We also measured cord blood FT(4) 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%]). 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 FT(4) 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 FT(4) 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 FT(4) 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. Our data provide the normative data for cord blood TSH and FT(4) 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.

Thyroid Profile of Term Appropriate for Gestational Age Neonates in Nigeria: A Forerunner to Screening for Congenital Hypothyroidism

Thyroid hormones in normal quantity are vital for physical growth and mental development during fetal and postnatal life. The available publications in Sub-Saharan Africa on the thyroid function of newborn infants was reported in babies delivered in moderate to severe goitre zones; utilizing the hormone levels from these studies may have a measure of bias. Newborn screening for congenital hypothyroidism (CH) in Sub-Saharan Africa is still a mirage, the technicality of the best timing for collection of blood samples need to be studied. Consequently, we report the serum levels of total thyroxine (T4), triiodothyronine (T3) and thyroid stimulating hormone (TSH) at birth and at 72 h after birth, and to ascertain if there is any significant difference between them. This was a prospective cross-sectional study (6 months period) between November and April 2005. One hundred and fourteen apparently healthy term AGA neonates had their thyroid function analyzed, the females (59) were slightly more in number than the (males 55). Most of them were between GA of 37-38 weeks at birth. The observed 72 h mean values of serum T3 and T4 (1.06 and 101.38 nmol l(-1)) compared with the cord values at birth (0.89 and 75.48 nmol l(-1)), was not statistically significant. The mean cord TSH levels (13.59 mU l(-1)) compared with 72 h serum TSH levels (10.25 mU l(-1)) was also insignificant p = 0.3. For Sub-Saharan Africa cord TSH analysis may be a reasonable choice for newborn screening for congenital hypothyroidism.

Prenatal exposure to organochlorine compounds and neonatal thyroid stimulating hormone levels

It has been suggested that prenatal exposure to some organochlorine compounds (OCs) may adversely affect thyroid function and may, therefore, impair neurodevelopment. The main aim of this study was to examine the relationship of cord serum levels of 1,1,1-trichloro-2,2-bis(4-chlorophenyl)ethane (4,4'-DDT), 1,1-dichloro-2,2-bis(4-chlorophenyl)ethylene (4,4'-DDE), β-hexachlorocyclohexane (β-HCH), hexachlorobenzene (HCB), four individual polychlorobiphenyl (PCB) congeners (118, 138, 153, and 180), and their sum, with neonatal thyroid stimulating hormone (TSH) levels in blood samples in a mother-infant cohort in Valencia, Spain. This study included 453 infants born between 2004 and 2006. We measured OC concentrations in umbilical cord serum and TSH in blood of newborns shortly after birth. Associations between neonatal TSH levels and prenatal OC exposure adjusted for covariates were assessed using multivariate linear regression analyses. Neonatal TSH levels tended to be higher in newborns with β-HCH levels in umbilical cord above 90th percentile (104 ng/g lipid) than in those with levels below the median (34 ng/g lipid), with an adjusted increment in neonatal TSH levels of 21% (95% confidence interval=-3, 51; P=0.09). No statistically significant association was found between the remaining OCs and TSH at birth. Prenatal exposure to β-HCH may affect neonatal thyroid hormone status and its function in neurological development.

Hypoechoic thyroid nodules on ultrasound 4 years after prenatal exposure to radioiodine: resolution with thyroxine therapy

We describe an infant inadvertently exposed to radioiodine at 17 weeks gestation. His mother had received 400 MBq of (131)I for hyperthyroidism (total T4 178 nmol/L, thyroid stimulating hormone (TSH) <0.1 mU/L, 4-h (131)I uptake 16%). Following cordocentesis at 27 weeks (free T4 12.7 pmol/L, TSH 35.4 mU/L) intra-amniotic thyroxine was withheld and a male infant was born at 39 weeks gestation, birthweight 3520 g. Cord TSH was low (0.1 mU/L), total T4 151 nmol/L on day 4, the mother having received no medication during pregnancy. Postnatal follow-up showed mild TSH elevation (11.0-19.4 mU/L) but normal free T4 (9-12.7 pmol/L) during the first 2 years of life following which the child was discharged still untreated. On recall at 4.3 years, TSH elevation persisted (15.4 mU/L) and ultrasound showed several hypoechoic thyroid nodules within the left lobe that disappeared after thyroxine treatment. In the event of inadvertent exposure to radioiodine in utero, the infant should receive thyroxine therapy from birth in order to protect the thyroid gland from TSH over-stimulation, however mild.

Cord Blood Thyroxine and Thyroid Stimulating Hormone Screening for Congenital Hypothyroidism: How Useful Are They?

To determine and compare the usefulness of cord blood screening for free thyroxine (FT4) and thyroid stimulating hormone (TSH). There is a vast amount of literature on capillary heel prick screening tests, but relatively little on cord blood testing particularly FT4. For a decade all infants born at Tawam Hospital had cord blood FT4 and at Oasis Hospital cord TSH measured through the hospital-based screening programme. On January 1st 1998, the national screening programme (NSP) for congenital hypothyroidism (CH) in the United Arab Emirates (UAE) started using capillary TSH measurement (Delfia method). Since then newborns in both hospitals have been screened both ways, i.e. cord blood and capillary blood screening. We reviewed retrospectively all infants born from January 1998 until the end of June 2004 with CH who had double screening: cord FT4 or TSH and 4th-5th day TSH screening. Thirteen infants (one in 1,778) had CH in Tawam Hospital. In six of these the cord blood FT4 was low (<9.1 pm/l) (0.73 ng/dl) and in seven the cord blood FT4 was normal, i.e., over half were missed. Eight infants (one in 1,198) had CH in the Oasis Hospital. Cord blood TSH was high in six of them (>13 IU/l) and two were normal. Cord FT4 detected the most severe cases, but missed most others. Cord TSH detected six out of eight cases, but there was a recall rate of one in 23. Cord FT4 identifies only infants with severe CH. Cord TSH is more sensitive than cord FT4 screening. Capillary TSH dried blood spot testing on the 3rd-5th day is the most sensitive method.

Maternal, Infant, and Delivery Factors Associated with Neonatal Thyroid Hormone Status

Thyroid function is dynamic during the perinatal period with many factors potentially influencing maternal, fetal and neonatal TSH and thyroid hormone levels. We sought to identify the impact of numerous maternal, fetal and delivery attributes on thyroid parameters in newborns. This was a cross sectional study of 300 newborns. Detailed information was obtained from medical records and multiple characteristics from the record were tested as predictors of cord blood serum total T4, free T4 and TSH and infant T4 levels from the Maryland newborn screening program. Outcomes are levels of thyroid stimulating hormone (TSH), thyroxine (T(4)), and free T(4) in newborn cord serum and total T(4) in postnatal heelstick bloodspot samples. Multivariate models identified a number of variables that are independently associated with thyroid hormone levels: higher birth order (lower cord TSH); older maternal age (lower cord total T(4)); pregnancy-induced hypertension and/or preeclampsia (lower cord total T(4) and free T(4)); gestational diabetes (higher cord free T(4)); sexually transmitted disease during pregnancy (lower cord TSH); alcohol use during pregnancy (lower cord TSH); thyroid condition/medications (higher bloodspot total T(4), both neonatal and subsequent); Asian ancestry (higher cord TSH); male sex (higher TSH and lower neonatal bloodspot total T(4)); and C-section (lower cord TSH). Gestational age was independently associated with lower cord TSH, higher cord total T(4), and higher neonatal and subsequent bloodspot total T(4). Fetal and newborn thyroid hormone levels during the perinatal period are dynamic and influenced by several biological and delivery related factors. Efforts to identify fetal thyroid disruptors in late gestation must carefully consider these factors.

Cadmium, Lead, and Selenium in Cord Blood and Thyroid Hormone Status of Newborns

Cadmium (Cd), lead (Pb), and selenium (Se) concentrations in cord whole blood, sampled from 24 women at the time of delivery in a hospital in Tokyo in 2005, were determined by inductively coupled plasma mass spectrometry with a reaction cell. Signal enhancement caused by nonspectroscopic interference for Se was evident and the standard addition technique was essential for correcting the interference. Median concentration in cord bloods was 0.20 ng/g, 6.7 ng/g (0.67 microg/dL), and 191 ng/g for Cd, Pb and Se, respectively. Lead concentration was lower, whereas Se concentration was higher, than those reported in other countries. The trace element concentration was related to the levels of thyroid stimulating hormone (TSH) and free thyroxin (fT4) in the neonatal blood sampled at 4-6 days postpartum. A significantly negative correlation was observed between Cd concentrations in cord blood and TSH concentration in neonatal blood. The result indicated the possible effect of in utero Cd exposure on thyroid hormone status of newborns and that Cd exposure level should be assessed as a covariate in the survey on the relationship between in utero chemicals (e.g., PCBs) exposure and thyroid hormone status.