Use of ultrasound to distinguish between fetal hyperthyroidism and hypothyroidism on discovery of a goiter

Fetal Hyperthyroidism with Maternal Hypothyroidism: Two Cases of Intrauterine Therapy

Fetal hyperthyroidism can occur secondary to maternal autoimmune hyperthyroidism. The thyroid-stimulating hormone receptor antibody (TRAb) transferred from the mother to the fetus stimulates the fetal thyroid and causes fetal thyrotoxicosis. Fetuses with this condition are difficult to detect, especially after maternal Graves disease therapy. Here, we present two cases of fetal hyperthyroidism with maternal hypothyroidism and review the assessment and intrauterine therapy for fetal hyperthyroidism. Both women were referred at 22+ and 23+ weeks of gestation with abnormal ultrasound findings, including fetal heart enlargement, pericardial effusion, and fetal tachycardia. Both women had a history of Graves disease while in a state of hypothyroidism with a high titer of TRAb. A sonographic examination showed a diffusely enlarged fetal thyroid with abundant blood flow. Invasive prenatal testing revealed no significant chromosomal aberration. Low fetal serum TSH and high TRAb levels were detected in the cord blood. Fetal hyperthyroidism was considered, and maternal oral methimazole (MMI) was administered as intrauterine therapy, with the slowing of fetal tachycardia, a reduction in fetal heart enlargement, and thyroid hyperemia. During therapy, maternal thyroid function was monitored, and the dosage of maternal levothyroxine was adjusted accordingly. Both women delivered spontaneously at 36+ weeks of gestation, and neonatal hyperthyroidism was confirmed in both newborns. After methimazole and propranolol drug treatment with levothyroxine for 8 and 12 months, both babies became euthyroid with normal growth and development.

Management of foetal hyperthyroidism in a mother with autoimmune hypothyroidism: A case report

Foetal hyperthyroidism is mediated by transplacental passage of thyroid stimulating antibodies (TSAbs) and affects mothers with autoimmune (AI) thyroid disease. We report a case of a 33-year-old woman with a history of AI hypothyroidism and raised TSI after 2 stillbirths with suspect foetal hyperthyroidism. At 20.5 gestational weeks (GW) of her third pregnancy, foetal tachycardia and goitre were detected. TSI levels were 30.9mUI/mL. Methimazole (MMI) was started and adjusted based on ultrasound signs (foetal heart rate and thyroid gland vascularisation). The neonate was born at 35GW and cord blood revealed decreased TSH and normal free T4. MMI was started in the neonate at 2 days of life due to the appearance of asymptomatic hyperthyroidism. This case illustrates a rare recurrence of foetal hyperthyroidism in a mother with AI hypothyroidism. Pregestational thyroidectomy, TSAbs determination, early ultrasound diagnosis and foetal therapy helped us to improve obstetric outcomes.

Fetal Goiter Diagnosed in a Euthyroid Patient: An Unusual Presentation of the Fetal Thyroid Disease

Fetal thyroid disease is rare, and the disease is mostly contextualized in the setting of a treated maternal thyroid disease. The presentation of thyroid disease in the fetus of a euthyroid mother is unusual. This paper presents the case of a 21-week pregnant woman with an incidental finding from a detailed anatomy ultrasound and evaluates available diagnostic and therapeutic management options. There is no consensus with sufficient evidence given the unusual presentation of this type of pathology. In most cases, the evidence is in the etiology of a mother with previous thyroid pathology that modifies the fetal outcome. Hence, it is important to describe cases to accumulate and, at some point, sufficient evidence of different treatments, with the intention of improving the quality of the recommendations. The management of fetal euthyroid goiter is a complex challenge. Most specialists manage the information on a case-by-case basis, with the same general goals as in patients with other thyroid pathologies.

Iodine and Thyroid Maternal and Fetal Metabolism during Pregnancy

Thyroid hormones and iodine are required to increase basal metabolic rate and to regulate protein synthesis, long bone growth and neuronal maturation. They are also essential for protein, fat and carbohydrate metabolism regulation. Imbalances in thyroid and iodine metabolism can negatively affect these vital functions. Pregnant women are at risk of hypo or hyperthyroidism, in relation to or regardless of their medical history, with potential dramatic outcomes. Fetal development highly relies on thyroid and iodine metabolism and can be compromised if they malfunction. As the interface between the fetus and the mother, the placenta plays a crucial role in thyroid and iodine metabolism during pregnancy. This narrative review aims to provide an update on current knowledge of thyroid and iodine metabolism in normal and pathological pregnancies. After a brief description of general thyroid and iodine metabolism, their main modifications during normal pregnancies and the placental molecular actors are described. We then discuss the most frequent pathologies to illustrate the upmost importance of iodine and thyroid for both the mother and the fetus.

Recommendations of the AGG (Working Group for Obstetrics, Department of Maternal Diseases) on How to Treat Thyroid Function Disorders in Pregnancy

Objective These recommendations from the AGG (Committee for Obstetrics, Department of Maternal Diseases) on how to treat thyroid function disorder during pregnancy aim to improve the diagnosis and management of thyroid anomalies during pregnancy.

Methods Based on the current literature, the task force members have developed the following recommendations and statements. These recommendations were adopted after a consensus by the members of the working group.

Recommendations The following manuscript gives an insight into physiological and pathophysiological thyroid changes during pregnancy, recommendations for clinical and subclinical hypo- and hyperthyroidism, as well as fetal and neonatal diagnostic and management strategies.

Thyroid autoantibodies

Thyroid-stimulating hormone (TSH) receptor antibody (TSH-R-Ab or TRAb) testing plays a pivotal role in arriving at the aetiological diagnosis in patients with thyrotoxicosis. A positive test establishes the diagnosis of Graves' disease (GD) while a negative result in conjunction with imaging studies supports other possible aetiologies. In patients with GD, TRAb levels at diagnosis and at the time of withdrawal of antithyroid drugs can identify patients who are unlikely to achieve remission and guide clinical management decisions. We provide an algorithm that incorporates TRAb in the decision-making process for the management of thyrotoxicosis. The utility of TRAb in predicting the risk of fetal and neonatal thyroid dysfunction is established and widely accepted in guidelines. TRAb may also help in the diagnosis of Graves' orbitopathy, especially in euthyroid or hypothyroid patients and its role in guiding its management is evolving as a useful adjunct to the clinical parameters used in making therapeutic decisions.Anti-thyroid peroxidase antibodies (TPOAb) and anti-thyroglobulin antibodies (TgAb) indicate thyroid autoimmunity. The most common use of TPOAb is to identify patients at a higher risk of progression to treatment-requiring hypothyroidism. They also aid the diagnosis of immune thyroiditis and Hashimoto's encephalopathy. Thyroglobulin measurement is used to help guide differentiated thyroid cancer treatment. TgAb is used as an accompanying test with thyroglobulin measurement as its presence can interfere with the thyroglobulin assay. A negative TgAb result reduces the likelihood of, but does not exclude, interference with thyroglobulin assay.

Immediate postnatal central hypothyroidism caused by maternal Graves' disease: Importance of early screening

This report illustrates a case of central hypothyroidism in a newborn immediately after birth caused by maternal Graves' disease. Infants from mothers with Graves' disease require careful examination without waiting for neonatal screening results, even though the mother's thyroid function is normal at birth or the newborn does not have goiter.

Timing of Graves' Hyperthyroidism Management in Pregnant Women: Impact on the Infant Thyroid Volume

The thyroid of the fetus of a mother with Graves’ disease (GD) is affected by the transplacental passage of both antithyroid drugs (ATDs) and thyroid-stimulating hormone receptor antibodies (TRAb). Thyroid hormone imbalances are harmful for the developing brain. This study aimed to evaluate the impact of the duration of antithyroid drug treatment in hyperthyroid pregnant women with GD on infants’ thyroid volume. Twenty-nine neonates born to mothers with GD were divided into two groups depending on the duration of ATDs treatment. The ultrasound thyroid volumes of the infants were measured within the first week of life. Thyroid-stimulating hormone, thyroxine, and TRAb values were recorded. There was no difference between groups in the thyroid hormones’ values. The median thyroid volume for the entire group of neonates with mothers with GD, for the groups of neonates of mothers with long- and short-treated GD, and for the control group were 1.539, 1.816, 1.347 and 1.014 mL, respectively. There were statistically significant differences in the thyroid volume between the GD group and the control group, as well as between the groups of neonates of mothers with long- and short-treated GD (p < 0.05). Studies have shown that the longer the duration of ATDs administration to mothers, the greater the thyroid volume of the neonate.

MANAGEMENT OF THYROTOXICOSIS AND PREGNANCY: Review of the current literature and an update of the care pathway

Pregnancy can be complicated by hyperthyroidism or thyrotoxicosis. Diagnosis is founded on an increase in free thyroid hormones and low TSH. The most frequent etiologies are Graves' disease, an autoimmune disease linked to stimulatory anti-TSH receptor antibodies, and non-autoimmune gestational hyperthyroidism linked to the TSH-like activity of the chorionic growth hormone (hCG). During pregnancy, thyrotoxicosis can entail maternal, obstetrical and fetal or neonatal complications. Graves' hyperthyroidism may be responsible for fetal and neonatal hyperthyroidism due to placental transfer of stimulatory anti-TSH receptor antibodies. During pregnancy, treatment of thyrotoxicosis must restore normal thyroid function in the mother without affecting fetal thyroid function. The recent reassessment of the prevalence of teratogenic effects in children of women treated with antithyroid drugs in the first weeks of gestation should orient the care pathway before and during pregnancy for women of child-bearing age with hyperthyroidism linked to Graves' disease.

Thyroid Disease in Pregnancy: A Descriptive Review of Guidelines

Importance

Thyroid disorders represent one of the most frequent complications of pregnancy associated with adverse obstetric, fetal, and neonatal outcomes, especially in case of delayed diagnosis and suboptimal management.

Objective

The aim of this study was to review and compare the recommendations of the most recently published guidelines on the diagnosis and management of these common conditions.

Evidence Acquisition

A descriptive review of guidelines from the Endocrine Society, the European Thyroid Association, the Royal Australian and New Zealand College of Obstetricians and Gynecologists, the American Thyroid Association, and the American College of Obstetricians and Gynecologists on thyroid disease in pregnancy was carried out.

Results

There is an overall consensus regarding the diagnosis of overt and subclinical hypothyroidism and hyperthyroidism in pregnancy using the pregnancy-specific reference ranges and the definition of postpartum thyroiditis. The reviewed guidelines unanimously discourage universal screening for thyroid function abnormalities before and during pregnancy and support targeted screening of high-risk patients by measuring serum thyroid-stimulating hormone levels. Moreover, they all highlight the need of treating overt hypothyroidism and hyperthyroidism, not only during pregnancy, but also before conception, suggesting similar management policies and treatment targets. There is also agreement regarding the management of gestational transient hyperthyroidism with hyperemesis gravidarum, suspected fetal thyrotoxicosis, postpartum thyroiditis, and thyroid malignancy. Scanning or treating with radioactive iodine is contraindicated during pregnancy and breastfeeding. On the other hand, there is controversy on the management of subclinical thyroid disease, thyroid function surveillance protocols, and iodine nutrition recommendations. Of note, the American College of Obstetricians and Gynecologists makes some specific recommendations on the treatment of thyroid storm and thyrotoxic heart failure in pregnant women, whereas the American Thyroid Association makes a special reference to the management of women with thyroid cancer.

Conclusions

As the disorders of the thyroid gland affect a significant proportion of pregnant women, it is of paramount importance to develop uniform international evidence-based protocols for their accurate diagnosis and optimal management, in order to safely guide clinical practice and eventually improve perinatal outcomes.

Hyperthyroidism in Pregnancy: The Delicate Balance between Too Much or Too Little Antithyroid Drug

Overt hyperthyroidism (HT) during pregnancy is associated with a risk of maternal–fetal complications. Antithyroid drugs (ATD) have a potential risk for teratogenic effects and fetal–neonatal hypothyroidism. This study evaluated ATD treatment and thyroid function control during pregnancy, and pregnancy outcome in women with HT. Patients and methods: A retrospective analysis of 36 single fetus pregnancies in 29 consecutive women (median age 30.3 ± 4.7 years) with HT diagnosed before or during pregnancy; a control group of 39 healthy euthyroid pregnant women was used. Results: Twenty-six women had Graves’ disease (GD, 33 pregnancies), 1 had a hyperfunctioning autonomous nodule, and 2 had gestational transient thyrotoxicosis (GTT). Methimazole (MMI) was administered in 22 pregnancies (78.5%), Propylthiouracil (PTU) in 2 (7.1%), switch from MMI to PTU in 4 (14.2%), no treatment in 8 pregnancies (3 with subclinical HT, 5 euthyroid with previous GD remission before conception). In the 8 pregnancies of GD patients diagnosed during gestation or shortly before (<6 weeks), i.e., with fetal exposure to uncontrolled HT, there was 1 spontaneous abortion at 5 weeks (3.4% of all ATD-treated pregnancies), and 1 premature delivery at 32 weeks with neonatal death in 24 h (3.4%); 1 child had neonatal hyperthyroidism (3.3% of live children in GD women) and a small atrial sept defect (4% of live children in ATD treated women). In women treated more than 6 months until conception (20 pregnancies): (a) median ATD doses were lower than those in women diagnosed shortly before or during pregnancy; (b) ATD was withdrawn in 40% of pregnancies in trimester (T)1, all on MMI < 10 mg/day (relapse in 14.2%), and in up to 55% in T3; (c) TSH level was below normal in 37%, 35% and 22% of pregnancies in T1, T2 and T3 respectively; FT4 was increased in 5.8% (T1) and subnormal in 11.75% in T2 and T3; (d) no fetal birth defects were recorded; one fetal death due to a true umbilical cord knot was registered. Mean birth weight was similar in both ATD-treated and control groups. Hyperthyroidism relapsed postpartum in 83% of GD patients (at median 3 ± 2.6 months). Conclusion: In hyperthyroid women with long-term ATD treatment before conception, drugs could be withdrawn in T1 in 40% of them, the thyroid function control was better, and pregnancy and fetal complications were rarer, compared to women diagnosed during pregnancy. Frequent serum TSH and FT4 monitoring is needed to maintain optimal thyroid function during pregnancy.

Prenatal management of fetal goiter alternating between hypothyroidism and hyperthyroidism in a mother with Graves' disease

We present a rare documented case with consecutive hypo- and hyperthyroidism during fetal life. First, hypothyroidism was due to transplacental passage of antithyroid drugs. After the mother's thyroidectomy, fetal hyperthyroidism was due to transplacental passage of persistent anti-thyrotropin receptor antibodies. Fetal goiter disappeared after adjusting maternal treatment.

Testing, Monitoring, and Treatment of Thyroid Dysfunction in Pregnancy

Both hyperthyroidism and hypothyroidism can have adverse effects in pregnancy. The most common causes of thyrotoxicosis in pregnancy are gestational transient thyrotoxicosis and Graves' disease. It is important to distinguish between these entities as treatment options differ. Women of reproductive age who are diagnosed with Graves' disease should be counseled regarding the impact of treatment options on a potential pregnancy. Although the absolute risk is small, antithyroid medications can have teratogenic effects. Propylthiouracil appears to have less severe teratogenicity compared to methimazole and is therefore favored during the first trimester if a medication is needed. Women should be advised to delay pregnancy for at least 6 months following radioactive iodine to minimize potential adverse effects from radiation and ensure normal thyroid hormone levels prior to conception. As thyroid hormone is critical for normal fetal development, hypothyroidism is associated with adverse obstetric and child neurodevelopmental outcomes. Women with overt hypothyroidism should be treated with levothyroxine (LT4) to a thyrotropin (thyroid-stimulating hormone; TSH) goal of <2.5 mIU/L. There is mounting evidence for associations of maternal hypothyroxinemia and subclinical hypothyroidism with pregnancy loss, preterm labor, and lower scores on child cognitive assessment. Although there is minimal risk of LT4 treatment to keep TSH within the pregnancy-specific reference range, treatment of mild maternal thyroid hypofunction remains controversial, given the lack of clinical trials showing improved outcomes with LT4 treatment.

Case Report: Functional Analysis and Neuropsychological Evaluation of Dyshormonogenetic Fetal Goiter in Siblings Caused by Novel Compound Hyterozygous TPO Gene Mutations

INTRODUCTION

It is rare for a euthyroid mother to carry a child with a fetal goiter. However, cases of congenital hypothyroidism (CH) caused by thyroid dyshormonogenesis have been reported. Even though gene mutations associated with fetal goiter have been reported in a few studies, the effects on intellectual development have not been investigated. This study aimed to characterize and investigate the underlying genetic mechanism of CH and neuropsychological development and growth of two siblings with CH-induced fetal goiters.

CASE REPORT

Two male siblings from a non-consanguineous marriage with CH and fetal goiter were diagnosed by ultrasonography at 32- and 26-weeks of gestation. This condition was confirmed by cordocentesis in the first pregnancy (TSH: 135 μIU/ml). The mother was euthyroid, and no intra-amniotic levothyroxine treatment was performed. Peripheral blood DNA was screened for TPO mutations. The new deletion p.Cys296Alafs*21 and the p.Arg665Trp mutation, inherited from heterozygous parents, were identified in both patients. Functional analysis showed both mutations reduced the TPO enzyme activity and impaired the membrane localization. The p.Cys296Alafs*21 mutation produces a protein product with a drastically reduced molecular weight. Additionally, a complete clinical and neuropsychological evaluation was also performed. The WISC IV test was employed to provide an overall measure of the siblings' cognitive and intellectual abilities. No growth retardation was detected in either child. In general, both children showed normal neuropsychological development; however, they exhibited slight reduction of Processing Speed Index scores, which are sensitive to neurological and attentional factors and motor maturation activity. Notably, the younger sibling obtained significantly low scores in the Operational Memory Index, a measure of attention capacity and psychoneurological immaturity.

CONCLUSION

We described a new TPO compound heterozygosity that severely impaired the TPO activity and membrane localization leading to severe CH and fetal goiter. This is the first report showing the neuropsychological evaluation in patients with dyshormonogenetic fetal goiter. More studies are needed to understand the neurodevelopmental outcomes of neonates with CH-induced fetal goiters.

Benefits and Risks of IgG Transplacental Transfer

Maternal passage of immunoglobulin G (IgG) is an important passive mechanism for protecting the infant while the neonatal immune system is still immature and ineffective. IgG is the only antibody class capable of crossing the histological layers of the placenta by attaching to the neonatal Fc receptor expressed at the level of syncytiotrophoblasts, and it offers protection against neonatal infectious pathogens. In pregnant women with autoimmune or alloimmune disorders, or in those requiring certain types of biological therapy, transplacental passage of abnormal antibodies may cause fetal or neonatal harm. In this review, we will discuss the physiological mechanisms and benefits of transplacental transfer of maternal antibodies as well as pathological maternal situations where this system is hijacked, potentially leading to adverse neonatal outcomes.

Ultrasonographic assessment of fetal thyroid in Japan: thyroid circumference and distal femoral and proximal tibial ossification

PURPOSE

The present study established a nomogram of fetal thyroid circumference (FTC) and the appearance timing of fetal distal femoral and proximal tibial ossification to assess fetal thyroid function in Japan.

METHODS

Between April 2015 and July 2019, normal pregnant women at our hospital were recruited for the study. FTC was measured by the automatic ellipse outline and plotted against gestational age (GA). Fetal distal femoral and proximal tibial ossification measurements were obtained with standard electronic calipers from outer-to-outer margins (> 1 mm as the presence of ossification).

RESULTS

A total of 199 pregnant women were examined. FTC increased logarithmically to GA. A nomogram of FTC was expressed by a logarithmic formula: [Formula: see text]. The respective 5-95th percentiles of FTC at each GA were 20.2-36.2 mm at 22 weeks, 25.0-44.8 mm at 26 weeks, 29.2-52.3 mm at 30 weeks, and 32.9-59.0 mm at 34 weeks. The fetal distal femoral epiphysis was not visualized before 30 weeks, but was visualized in 100% of fetuses after 35 weeks of gestation. The fetal proximal tibial epiphysis was not visualized before 33 weeks, but was visualized in 73.7% of fetuses at 37 weeks of gestation.

CONCLUSION

We generated a GA-dependent FTC nomogram for Japanese fetuses. We also confirmed the appearance timing of fetal distal femoral and proximal tibial ossification to assess bone maturation. These assessments may be very useful for evaluating fetal thyroid function in Japan.

Fetal goiter identified in a pregnant woman with triiodothyronine-predominant graves' disease: a case report

BACKGROUND

Approximately 10% of all Graves' disease cases are triiodothyronine (T3)-predominant. T3-predominance is characterized by higher T3 levels than thyroxine (T4) levels. Thyroid stimulating hormone receptor autoantibody (TRAb) levels are higher in T3-predominant Graves' disease cases than in non-T3-predominant Graves' disease cases. Treatment with oral drugs is difficult. Here, we report a case of fetal goiter in a pregnant woman with T3-predominant Graves' disease.

CASE PRESENTATION

A 31-year-old woman had unstable thyroid function during the third trimester of pregnancy, making it impossible to reduce her dosage of antithyroid medication. She was admitted to our hospital at 34 weeks of gestation owing to hydramnios and signs of threatened premature labor, and fetal goiter (thyromegaly) was detected. The dose of her antithyroid medication was reduced, based on the assumption that it had migrated to the fetus. Subsequently, the fetal goiter decreased in size, and the hydramnios improved. The patient underwent elective cesarean delivery at 36 weeks and 5 days of gestation. The infant presented with temporary symptoms of hyperthyroidism that improved over time.

CONCLUSIONS

The recommended perinatal management of Graves' disease is to adjust free T4 within a range from the upper limit of normal to a slightly elevated level in order to maintain the thyroid function of the fetus. However, in T3-predominant cases, free T4 levels may drop during the long-term course of the pregnancy owing to attempts to control the mother's symptoms of thyrotoxicosis. Little is known about the perinatal management and appropriate therapeutic strategy for T3-predominant cases and fetal goiter. Therefore, further investigation is necessary.

Conservative in utero treatment of fetal dyshormonogenetic goiter with levothyroxine, a systematic literature review

Fetal goitrous hypothyroidism is a rare condition associated with important obstetrical, neonatal complications, and neurodevelopmental impairments. Prenatal treatment remains controversial, and the risk to benefit ratio must be accurately assessed and considered for individualized management. The objective of this review was to evaluate the feasibility, safety, and effectiveness of the conservative in utero treatment of fetal goitrous hypothyroidism. In total, 25 reports that met our inclusion criteria were selected and the management of 38 cases was analyzed. Prenatal diagnosis consisted mainly of ultrasonographic findings. Fetal thyroid status was assessed by cordocentesis. Prenatal treatment varied widely in terms of levothyroxine (LT4) route of administration, dosage, number of injections, and frequency. Although different regimens and routes of administration were proposed, they seem to have similar results regarding fetal goiter reduction and thyroid status at birth. At birth, most babies had hypothyroidism, but the long-term follow-up indicated a normal psycho-neuromotor development. Our data confirm the feasibility of conservative treatment with LT4 for fetal goitrous hypothyroidism. Further studies are needed to determine the optimal management of this disorder.

Maternal and Fetal Thyroid Physiology

This study was a brief review of maternal and fetal thyroid function and pathology during pregnancy.

Neonatal Thyroid Function and Disorders

Thyroid hormone is essential for normal fetal brain development in utero and for the first 2 years of life. The developing fetus is initially reliant upon maternal thyroid hormones that cross the placenta, until the fetal thyroid begins to supply thyroid hormone for the fetus. Maternal thyroid status affects fetal thyroid function and maternal thyroid dysfunction can have a significant impact on the fetus and neonate. There are also several neonatal factors that can influence thyroid function. Here, we describe thyroid function in the fetus and neonate and discuss the most common thyroid disorders seen in neonates.

Iatrogenic fetal goiter. Conservative management and spontaneous resolution

Objectives

We aim to report a case of a fetal goiter with postpartum spontaneous resolution. Fetal goiter can be secondary to maternal treatment and range from clinically asymptomatic or cause alterations in the fetus, from impaired swallowing to difficulty in vaginal delivery and even perinatal asphyxia due to the mass effect. The need for intrauterine treatment remains controversial.

Case presentation

We present a case of fetal goiter with postpartum resolution. A 34-year-old multigravida presented to the emergency department with hiperemesis gravidarum at 10 weeks’ gestation. During evaluation for severe vomiting, Graves disease was diagnosed and treated with propylthiouracil. A routine ultrasound scan at 28 weeks gestation revealed a fetal anterior neck mass suggesting a fetal goiter. Cordocentesis showed fetal iatrogenic hypothyroidism. Conservative treatment was decided. Pregnancy concluded uneventful and the mass resolved spontaneously in the newborn.

Conclusions

The fetal thyroid gland is a structure that usually goes unnoticed during the process of prenatal diagnosis. In cases of maternal Graves diseases, fetal thyroid needs monitoring during pregnancy and conservative treatment is an option. Fetal goiter should be searched for secondary to thyroid alterations of the gravida, and in selected cases it can be managed without intrauterine treatment.

Current knowledge about the in utero and peripartum management of fetal goiter associated with maternal Graves' disease

Maternal Graves’ disease is the most common cause of fetal goiter. Fetal goiter can cause complications attributable either to the physical effects of the goiter itself or to thyroid dysfunction, which can be life-threatening and cause neurological impairment. Determining whether a goiter is caused by fetal hyperthyroidism or hypothyroidism is the main clinical problem, and in utero evaluations and management are essential. Ultrasonography combined with color Doppler and magnetic resonance imaging are helpful for the initial diagnosis and monitoring, but these imaging techniques have a limited ability to discriminate between fetal hyperthyroidism and hypothyroidism. To determine the fetal thyroid status, fetal blood sampling using cordocentesis is reliable but hazardous, and the indications must be considered carefully. Amniocentesis is an easier and safer alternative, but the correlations between the amniotic fluid and fetal serum thyroid hormone levels remain unclear. If a fetal goiter is accompanied by hypothyroidism, administering thyroid hormone intra-amniotically may be effective and relatively safe. However, the wide variety of approaches to treatment exemplifies the lack of guidelines, and no systematic studies have been conducted to date. Therefore, intrauterine treatment should be reserved for selected patients at a high risk of complications. Moreover, when intrauterine treatment fails and a fetal goiter can cause airway obstruction, intrapartum management, such as ex utero intrapartum treatment, may be required; however, reports describing the use of this procedure for fetal goiter are limited. This review summarizes the current knowledge about fetal goiter associated with maternal Graves’ disease and evaluates the most significant new findings regarding its in utero and peripartum management.

Management of fetal goiters: 6-year retrospective observational study in three prenatal diagnosis and treatment centers of the Pays De Loire Perinatal Network

Introduction: The incidence of fetal goiters is reported to be around 1 per 40,000 births. The risk of complications is first of all obstetric, directly related to goiter size, but it may also affect longer term fetal and child development, depending on whether the goiter is due to hypo- or hyperthyroidism. Management is multidisciplinary, but not yet consensual and not always optimal by either endocrinologists or obstetricians.Objectives: The principal objective of this retrospective study was to analyze the data that enabled the physicians to assess whether the goiter was hypo- or hyperthyroid and then to analyze the obstetric practices used in the Pays de Loire network to describe in detail the tools used to diagnose and characterize the goiters and the management chosen in these cases. The secondary objectives are to assess, in our small cohort, the effectiveness of the in utero treatments provided, based on the examination of the children at birth and their outcome at 6 months of life, and to suggest a strategy for monitoring these women at risk that takes current guidelines into consideration.Materials and methods: This multicenter retrospective study covers a 6-year period and focused on the prenatal diagnosis centers (CPDPN) of the Pays de Loire perinatal network: in Nantes, Angers, and Le Mans. The network is responsible for around 42,000 births a year, and the study included 17 women, for a prevalence of 1 per 15,000 births.Results: Ten of the 17 fetuses had a hypothyroid goiter, 4 a hyperthyroid goiter, and 3 normal thyroid findings on fetal blood sample (FBS). For four women, these goiters were secondary to fetal dyshormonogenesis, for 9 more to Graves disease with TSH receptor antibodies (TRAb), and for four women to thyrotoxicosis at the start of pregnancy, managed by synthetic antithyroid drugs. Two newborns had severe complications associated with maternal transmission of Graves disease (TRAb positive at birth): one with exophthalmos and one with neonatal tachycardia. The other 14 had normal psychomotor development at 6 months, based on a clinical examination by a pediatric endocrinologist; only one child was lost to follow-up.Conclusion: Together, ultrasound and multidisciplinary expertise (of an endocrinologist and an obstetrician experienced with this disease) remain the best means for avoiding, or otherwise for accurately characterizing fetal goiter. An ultrasound diagnostic score, of the type proposed by Luton et al. in 2009, may make it possible to homogenize practices and thus to defer or delay the - currently too common - performance of invasive FBS procedures, which must remain rare in this management to limit comorbidities. A threshold TRAb value (>5 IU/l) makes it possible to define this group of women as at risk of fetal and neonatal hyperthyroidism and thus requiring close monitoring. The value of prenatal intra-amniotic thyroxine treatment for hypothyroid goiters (including dyshormonogenesis) remains to be demonstrated.

MANAGEMENT OF THYROTOXICOSIS: PRECONCEPTION, PREGNANCY, AND THE POSTPARTUM PERIOD

OBJECTIVE

To review the diagnosis and management of thyrotoxicosis in women who are preconception, pregnant, and in the postpartum period.

METHODS

Literature review of English-language papers published between 1980 and 2018.

RESULTS

Overt thyrotoxicosis occurs in 0.2% of pregnancies and subclinical thyrotoxicosis in 2.5%. Hyperthyroidism in women of childbearing age most frequently is caused by Graves disease (GD). Gestational thyrotoxicosis, transient human chorionic gonadotropin (hCG)-mediated hyperthyroidism, may develop in the first trimester. In the first year following delivery, postpartum thyroiditis, which frequently includes a thyrotoxic phase, occurs in 5% of women. Hyperthyroidism from nodular autonomy is uncommon in women of childbearing age. It is essential to understand the underlying etiology for thyrotoxicosis in order to recommend appropriate treatment. Gestational thyrotoxicosis requires supportive care, without antithyroid drug therapy. GD may be treated with antithyroid drugs, radioactive iodine, or thyroidectomy. Pregnancy, plans for pregnancy, and lactation have important implications for the choice of GD treatment. When thyrotoxicosis presents following delivery, postpartum thyroiditis must be differentiated from GD.

CONCLUSION

The diagnosis and management of thyrotoxicosis in the peripregnancy period present specific challenges. In making management decisions, it is essential to weigh the risks and benefits of treatments not just for the mother but also for the fetus and for breastfed infants. A team approach to management is critical, with close collaboration among endocrinologists, maternal-fetal medicine specialists, and neonatologists.

ABBREVIATIONS

GD = Graves disease; hCG = human chorionic gonadotropin; MMI = methimazole; PPT = postpartum thyroiditis; PTU = propylthiouracil; T3 = triiodothyronine; T4 = thyroxine; TBG = thyroxine-binding globulin; TRAb = TSH receptor antibody; TSH = thyroid-stimulating hormone.

Study of the Factors Leading to Fetal and Neonatal Dysthyroidism in Children of Patients With Graves Disease

CONTEXT

Neonatal hyperthyroidism was first described in 1912 and in 1964 was shown to be linked to transplacental passage of maternal antibodies. Few multicenter studies have described the perinatal factors leading to fetal and neonatal dysthyroidism.

OBJECTIVE

To show how fetal dysthyroidism (FD) and neonatal dysthyroidism (ND) can be predicted from perinatal variables, in particular, the levels of anti-thyrotropin receptor antibodies (TRAbs) circulating in the mother and child.

DESIGN AND PATIENTS

This was a retrospective multicenter study of data from the medical records of all patients monitored for pregnancy from 2007 to 2014.

SETTING

Among 280,000 births, the medical records of 2288 women with thyroid dysfunction were selected and screened, and 417 women with Graves disease and positive for TRAbs during pregnancy were included.

RESULTS

Using the maternal TRAb levels, the cutoff value of 2.5 IU/L best predicted for FD, with a sensitivity of 100% and specificity of 64%. Using the newborn TRAb levels, the cutoff value of 6.8 IU/L best predicted for ND, with a sensitivity of 100% and a specificity of 94%. In our study, 65% of women with a history of Graves disease did not receive antithyroid drugs during pregnancy but still had infants at risk of ND.

CONCLUSIONS

In pregnant women with TRAb levels ≥2.5 IU/L, fetal ultrasound monitoring is essential until delivery. All newborns with TRAb levels ≥6.8 IU/L should be examined by a pediatrician with special attention for thyroid dysfunction and treated, if necessary.

2017 Guidelines of the American Thyroid Association for the Diagnosis and Management of Thyroid Disease During Pregnancy and the Postpartum

BACKGROUND

Thyroid disease in pregnancy is a common clinical problem. Since the guidelines for the management of these disorders by the American Thyroid Association (ATA) were first published in 2011, significant clinical and scientific advances have occurred in the field. The aim of these guidelines is to inform clinicians, patients, researchers, and health policy makers on published evidence relating to the diagnosis and management of thyroid disease in women during pregnancy, preconception, and the postpartum period.

METHODS

The specific clinical questions addressed in these guidelines were based on prior versions of the guidelines, stakeholder input, and input of task force members. Task force panel members were educated on knowledge synthesis methods, including electronic database searching, review and selection of relevant citations, and critical appraisal of selected studies. Published English language articles were eligible for inclusion. The American College of Physicians Guideline Grading System was used for critical appraisal of evidence and grading strength of recommendations. The guideline task force had complete editorial independence from the ATA. Competing interests of guideline task force members were regularly updated, managed, and communicated to the ATA and task force members.

RESULTS

The revised guidelines for the management of thyroid disease in pregnancy include recommendations regarding the interpretation of thyroid function tests in pregnancy, iodine nutrition, thyroid autoantibodies and pregnancy complications, thyroid considerations in infertile women, hypothyroidism in pregnancy, thyrotoxicosis in pregnancy, thyroid nodules and cancer in pregnant women, fetal and neonatal considerations, thyroid disease and lactation, screening for thyroid dysfunction in pregnancy, and directions for future research.

CONCLUSIONS

We have developed evidence-based recommendations to inform clinical decision-making in the management of thyroid disease in pregnant and postpartum women. While all care must be individualized, such recommendations provide, in our opinion, optimal care paradigms for patients with these disorders.

Fetal neonatal hyperthyroidism: diagnostic and therapeutic approachment

Fetal and neonatal hyperthyroidism may occur in mothers with Graves' disease. Fetal thyrotoxicosis manifestation is observed with the transition of TSH receptor stimulating antibodies to the fetus from the 17th-20th weeks of pregnancy and with the fetal TSH receptors becoming responsive after 20 weeks. The diagnosis is confirmed by fetal tachycardia, goiter and bone age advancement in pregnancy and maternal treatment is conducted in accordance. The probability of neonatal hyperthyroidism is high in the babies of mothers that have ongoing antithyroid requirement and higher antibody levels in the last months of pregnancy. Clinical manifestation may be delayed by 7-17 days because of the antithyroid drugs taken by the mother. Neonatal hyperthyroidism symptoms can be confused with sepsis and congenital viral infections. Herein, the diagnosis and therapeutic approach are reviewed in cases of fetal neonatal hyperthyroidism.

The role of prenatal ultrasound assessment in management of fetal cervicofacial tumors

Ultrasound prenatal examination enables one to assess the facial skeleton and the neck from the first weeks of gestation. Cervicofacial tumors detected via prenatal ultrasound are very rarely reported fetal pathologies. They include cystic hygromas, teratomas, epulides, vascular tumors, and thyroid tumors. The tumor category, its location and vascularization pattern allow one to accurately establish a diagnosis which is usually confirmed by clinical examination of the neonate or a pathological examination (surgical specimen, biopsy, autopsy). The prenatal ultrasound diagnosis of cervicofacial tumor in the fetus allows planning of pregnancy management and fetal therapy, preparation of the delivery, and perinatal as well as neonatal treatment.

Fetal goiter conservatively monitored during the prenatal period associated with maternal and neonatal euthyroid status

Congenital goiter is considered a rare occurrence, and may be related to hypothyroidism, hyperthyroidism, or euthyroidism. In this report, we describe a case of fetal goiter identified in the 34th gestational week in a 41-year-old secundigravida with normal thyroid functions. A conservative approach was followed; the fetal goiter was monitored via ultrasound, which suggested this was a case of hyperthyroidism. After the birth, tests indicated that the newborn was euthyroidic. Consequently, a more detailed study using non-invasive procedures was deemed necessary to discover the precise cause of the fetal goiter during the gestational period.

Prenatal Diagnosis and Treatment of Fetal Goiter

A case study of a fetal goiter with successful in utero treatment is presented. The incidence of fetal goiters is rare and can have poor neonatal outcomes due to tracheal and esophageal obstruction. This makes prenatal diagnosis and treatment pertinent. In this case, a solid, homogenous, hypervascular mass is seen protruding from the anterior fetal neck causing hyperextension of the cervical spine. With the use of a percutaneous umbilical cord sampling (PUBS) procedure, the diagnosis of fetal hypothyroidism was established. Successful treatment of the fetal goiter and hypothyroidism with intra-amniotic injections of synthroid prevented tracheal obstruction and the need for an ex utero intrapartum treatment (EXIT) procedure at delivery.

Retrospective chart review of 44 fetuses with cervicofacial tumors in the sonographic assessment

OBJECTIVES

The aim of this retrospective study was to review and analyze ultrasonography examinations and follow-up of fetuses with cervicofacial tumors to develop bases for counseling specialist involved in perinatal treatment.

METHODS

The study consisted of case series with chart review of 44 fetuses with cervicofacial tumors diagnosed in utero by ultrasonography. The study was carried in Department of Diagnosis and Prevention of Congenital Malformations, Medical University of Lodz in years 1998-2013. The analysis of the fetuses with cervicofacial tumors included assessment of fetal sonographic features, neonatal survival and in utero as well as perinatal treatments. The obtained data were analyzed by the standard statistical tests and the Pearson's Chi square test, statistical significance at p=0.05.

RESULTS

Cervicofacial tumors were detected at mean 19±7 weeks of gestation. Eighty-two percent of the fetuses were males. Lymphatic malformations followed by teratomas were the most common fetal tumors in the cervicofacial region. In most cases, fetuses with cervicofacial tumors had other abnormalities. Mortality rate in our case series was 43%. In utero treatment was introduced in 6 fetuses. In 4 neonates prenatal sonographic assessment revealed upper airway patency and EXIT procedure (ex-utero intrapartum treatment) was introduced.

CONCLUSION

Prenatal sonographic detection of cervicofacial tumor, in case of lymphatic malformations possibly as early as in the first trimester, in case of craniofacial teratomas, cervical teratomas, hemangiomas and thyroid tumors possibly as early as in the second trimester, and in case of epignathi possibly in the third trimester, permits planning further course of pregnancy as well as EXIT procedure before delivery.

European Society for Paediatric Endocrinology consensus guidelines on screening, diagnosis, and management of congenital hypothyroidism

OBJECTIVE

The aim was to formulate practice guidelines for the diagnosis and management of congenital hypothyroidism (CH).

EVIDENCE

A systematic literature search was conducted to identify key articles relating to the screening, diagnosis, and management of CH. The evidence-based guidelines were developed with the Grading of Recommendations, Assessment, Development and Evaluation (GRADE) system, describing both the strength of recommendations and the quality of evidence. In the absence of sufficient evidence, conclusions were based on expert opinion.

CONSENSUS PROCESS

Thirty-two participants drawn from the European Society for Paediatric Endocrinology and five other major scientific societies in the field of pediatric endocrinology were allocated to working groups with assigned topics and specific questions. Each group searched the literature, evaluated the evidence, and developed a draft document. These papers were debated and finalized by each group before presentation to the full assembly for further discussion and agreement.

RECOMMENDATIONS

The recommendations include: worldwide neonatal screening, approaches to assess the cause (including genotyping) and the severity of the disorder, the immediate initiation of appropriate L-T4 supplementation and frequent monitoring to ensure dose adjustments to keep thyroid hormone levels in the target ranges, a trial of treatment in patients suspected of transient CH, regular assessments of developmental and neurosensory functions, consulting health professionals as appropriate, and education about CH. The harmonization of diagnosis, management, and routine health surveillance would not only optimize patient outcomes, but should also facilitate epidemiological studies of the disorder. Individuals with CH require monitoring throughout their lives, particularly during early childhood and pregnancy.

Antenatal diagnosis and treatment of hypothyroid fetal goiter in an euthyroid mother: a case report and review of literature

Fetal goiter is an extremely rare complication of pregnancy. Its incidence is 1 in 40,000 deliveries. Antithyroid maternal therapy is responsible for 10-15% of fetal congenital hypothyroidism and can be considered as the most frequent underlying cause for this condition. The frequency of fetal goiter that is associated with fetal hypothyroidism and normal maternal thyroid function, as in our case, is even less frequent. Fetal goiter is associated with increased rate of perinatal complications and long-term morbidity, due to peripartum complications including labor dystocia due to its mass effect, as well as neonatal airway obstruction that may lead to hypoxic-ischemic brain injury and death. We present, in this study, a case report of late antenatal fetal goiter in an euthyroid woman and a literature review of the diagnosis and treatment of these cases.

A case of fetal hyperthyroidism treated with maternal administration of methimazole

Prenatal ultrasonography of a pregnant woman with a past history of total thyroidectomy for Graves' disease detected fetal tachycardia, fetal growth restriction and oligohydramnios at 30 weeks gestation. Because a high titer of thyroid-stimulating hormone receptor antibody was noted in maternal serum and the fetal goiter was detected on ultrasonography, fetal hyperthyroidism was strongly suspected and subsequently confirmed with cordocentesis at 31 weeks gestation. After treatment of fetal hyperthyroidism through oral maternal administration of methimazole (MMI) starting at 33 weeks gestation, fetal heart rate and amniotic fluid volume returned to normal ranges. Complete resolution of the fetal goiter was observed at 35 weeks gestation. A male infant was born at 35 weeks 6 days gestation via cesarean section in the absence of thyrotoxic findings; however, cord blood chemical analysis at birth indicated iatrogenic fetal hypothyroidism. In the present report, maternal therapy using MMI to resolve symptoms of fetal thyrotoxicosis, including fetal tachycardia and oligohydramnios, was successfully conducted.

Thyrotoxicosis of Pregnancy

Thyrotoxicosis presenting during pregnancy is a common clinical problem and can be challenging to differentiate between physiologic patterns of thyroid dysfunction during gestation and intrinsic hyperthyroidism. This review provides a summary of the differential diagnosis, clinical presentation, diagnostic options, potential adverse effects of maternal thyrotoxicosis to the fetus, and treatment recommendations for thyrotoxicosis arising in pregnancy.

Management of neonates born to women with Graves' disease: a cohort study

OBJECTIVE

Hyperthyroidism in neonates born to mothers with Graves' disease (GD) can be associated with significant morbidity and mortality, but is still overlooked by clinicians. Management of neonatal hyperthyroidism would be improved by a better understanding of the predictive factors involved. The aim of this study was to evaluate the course of thyroid function and clinical outcomes during the first postnatal month in babies born to mothers with GD.

DESIGN

Prospective observational study.

METHODS

Sixty-eight neonates born to mothers with GD were managed from birth and divided into three groups based on thyrotropin receptor antibody (TRAb) and anti-thyroid drug (ATD) status in the mother: TRAb(-ve)/ATD(-ve), n=27; TRAb(-ve)/ATD(+) (ve), n=8; and TRAb(+ve)/ATD(+ve), n=33. The main outcome measures were clinical examination, thyroid function tests (TSH, free thyroxine (FT4), free triiodothyronine, and TRAb), echocardiography, thyroid ultrasonography, and bone maturation assessment.

RESULTS

None of the infants born to TRAb(-ve) mothers with GD developed neonatal hyperthyroidism. Of the 33 TRAb(+ve)/ATD(+ve) neonates, 24 (72.7%) had positive TRAb on cord blood assays, and seven of these developed neonatal hyperthyroidism. FT4 elevation between days 3 and 7 but not at birth was predictive of the development of hyperthyroidism.

CONCLUSIONS

TRAb status should be checked in the third trimester in mothers with GD and on cord blood in their neonates; if positive, it indicates a high risk of neonatal hyperthyroidism. FT4 measurement at birth should be repeated between days 3 and 5 (and by day 7 at the latest); rapid FT4 elevation during the first postnatal week is predictive of hyperthyroidism and warrants ATD therapy.

Thyroid disorders during pregnancy

Thyroid disorders are common in pregnancy and in nonpregnant women of childbearing age, but can be missed because of nonspecific symptoms and normal changes in thyroid gland physiology during pregnancy. The prevalence of overt hyperthyroidism complicating pregnancy has been reported to range between 0.4% and 1.7%, and an estimated 2% to 3% of women are hypothyroid during pregnancy. Abnormalities in maternal thyroid function are associated with complications during pregnancy, and may affect maternal and fetal outcomes. Thus it is important to identify thyroid disorders before pregnancy or early in pregnancy so that appropriate treatment can be initiated.

Sonographic Diagnosis of Fetal Goiter

The presence of a goiter in the fetus is an indication of maternal thyroid dysfunction. It carries an increased morbidity and mortality for the fetus and into the neonatal period. Maternal thyroid disease must be monitored closely and medications adjusted throughout pregnancy to prevent adverse outcomes. In females with poorly controlled thyroid disease, sonography is useful in the evaluation of the fetus at risk for goiter.

Fetal thyroïdology

Advances in prenatal imaging techniques and in fetal hormonology now allow for identification of disorders of thyroid function in the fetus. These can potentially be treated in utero by giving drugs to the mother. This review shows the feasibility of in utero treatment of fetal thyroid disorders, either indirectly by treating the mother or by giving the necessary drugs directly to the fetus. For goitrous fetal hypothyroidism leading to hydramnios, repeated intra-amniotic injections of thyroxine have been reported to decrease the size of the fetal thyroid. Experience with such procedures is limited but positive. The risk that direct in utero treatment of the fetus may provoke premature labor or cause infection should be carefully evaluated. In women with Graves' disease, autoimmune fetal hyperthyroidism can generally be treated in a noninvasive way by optimizing treatment of the mother, such as by increasing the dose of antithyroid drugs. Follow-up of the efficacy and the possible long-term consequences of medical interventions to normalize thyroid function of the fetus are of great importance. Specialized care of the fetus should be provided by skilled teams with extensive experience in prenatal care.

European Society for Paediatric Endocrinology consensus guidelines on screening, diagnosis, and management of congenital hypothyroidism

OBJECTIVE

The aim was to formulate practice guidelines for the diagnosis and management of congenital hypothyroidism (CH).

EVIDENCE

A systematic literature search was conducted to identify key articles relating to the screening, diagnosis, and management of CH. The evidence-based guidelines were developed with the Grading of Recommendations, Assessment, Development and Evaluation (GRADE) system, describing both the strength of recommendations and the quality of evidence. In the absence of sufficient evidence, conclusions were based on expert opinion.

CONSENSUS PROCESS

Thirty-two participants drawn from the European Society for Paediatric Endocrinology and five other major scientific societies in the field of pediatric endocrinology were allocated to working groups with assigned topics and specific questions. Each group searched the literature, evaluated the evidence, and developed a draft document. These papers were debated and finalized by each group before presentation to the full assembly for further discussion and agreement.

RECOMMENDATIONS

The recommendations include: worldwide neonatal screening, approaches to assess the cause (including genotyping) and the severity of the disorder, the immediate initiation of appropriate L-T4 supplementation and frequent monitoring to ensure dose adjustments to keep thyroid hormone levels in the target ranges, a trial of treatment in patients suspected of transient CH, regular assessments of developmental and neurosensory functions, consulting health professionals as appropriate, and education about CH. The harmonization of diagnosis, management, and routine health surveillance would not only optimize patient outcomes, but should also facilitate epidemiological studies of the disorder. Individuals with CH require monitoring throughout their lives, particularly during early childhood and pregnancy.

Conservatively managed fetal goiter: an alternative to in utero therapy

Fetal goiter may arise from a variety of etiologies including iodine deficiency, overtreatment of maternal Graves' disease, inappropriate maternal thyroid replacement and, rarely, congenital hypothyroidism. Fetal goiter is often associated with a retroflexed neck and polyhydramnios, raising concerns regarding airway obstruction in such cases. Prior reports have advocated for cordocentesis and intra-amniotic thyroid hormone therapy in order to confirm the diagnosis of fetal thyroid dysfunction, reduce the size of the fetal goiter, reduce polyhydramnios, aid with the assistance of maternal thyroid hormone therapy and reduce fetal malpresentation. We report two cases of conservatively managed fetal goiter, one resulting in a vaginal delivery, and no evidence of postnatal respiratory distress despite the presence of polyhydramnios and a retroflexed neck on prenatal ultrasound.

Size and location of thyroid gland in the fetal period

PURPOSE

The present study's purpose was to examine the size and location of the thyroid gland using anatomic dissection methods on fetal cadavers.

METHODS

This study was performed on 200 spontaneously aborted human fetuses (100 males and 100 females) aged between 9 and 40 weeks of gestation. Fetuses without any external and internal pathology or anomaly were included in this study. Fetuses were divided into four groups based on gestational ages as follows: first group 9-12 weeks (first trimester), second group 13-25 weeks (second trimester), third group 26-37 weeks (third trimester) and fourth group 38-40 weeks (full term). The fetuses were also grouped into monthly cohorts as follows: 9-12 weeks, 3rd month; 13-16 weeks, 4th month; 17-20 weeks, 5th month; 21-24 weeks, 6th month; 25-28 weeks, 7th month; 29-32 weeks, 8th month; 33-36 weeks, 9th month; and 37-40 weeks, 10th month. The anterior necks of fetuses were dissected and the thyroid glands exposed. Vertebral and laryngeal levels and the dimensions (width, length, thickness and weight) of the fetal thyroid glands were determined by anatomical dissection methods. The dimensions and ratios of the fetal thyroid gland (weight/fetal body weight) were evaluated.

RESULTS

The mean values and standard deviations of all parameters by gestational weeks, months, and trimesters were calculated. It was found that all parameters increased with gestational age. No significant differences were observed between genders in all parameters (P > 0.05). There were no significant differences between the right and the left sides for parameters of the thyroid glands. The levels of the superior poles of the thyroid lobes were located at the cervical (C) C1-C3 vertebral bodies. The levels of the inferior poles of the thyroid lobes were located at C4-C5 vertebral bodies. The levels of the superior poles of thyroid lobes were located between the upper ½ and lower ½ of the thyroid cartilage or cricoid cartilage. The levels of the inferior poles of the thyroid lobes were located between the second and sixth tracheal rings. The distance between the superior poles of the thyroid gland and the hyoid bone increased throughout the fetal period. The dimensions of fetal thyroid glands increased with gestational age. The ratio between thyroid gland weights and fetal body weights was unchanged during the fetal period.

CONCLUSIONS

We believe that the results obtained from this study will be useful in monitoring thyroid glands in the intrauterine period as well as recognizing early diagnosis and treatment of thyroid anomalies. It will also contribute to future studies in obstetrics, perinatology, and fetopathology.

Correlation of nuchal translucency and thyroxine at 11-13 weeks of gestation

OBJECTIVE

Nuchal translucency (NT) thickness is one of the major screening markers during the first trimester that could be influenced by several factors. Here, we investigated the association between NT thickness and thyroid related hormones.

METHODS

NT thickness was measured with transabdominal ultrasound in 643 pregnant women between 11 and 13 weeks of gestation. Maternal thyroxine (T4), free thyroxine (fT4) and thyroid-stimulating hormone (TSH) were evaluated. Bivariate correlations were assessed and thyroid profile was subcategorized with regard to the calculated reference ranges.

RESULTS

An inverse relation was found between serum levels of maternal T4 with NT thickness (r = -0.128, p = 0.001) and CRL (r = -0.168, p < 0.001). TSH and hCG were also found to be correlated (Spearman's correlation coefficient = -0.092, p = 0.019). Prevalence of maternal hypothyroidism and subclinical hypothyroidism were 1.1% and 3.7%, respectively.

CONCLUSION

Thyroid function tests are found to independently influence NT measurements in the first trimester. Assessment of hormones such as thyroxine could optimize the interpretation of screening tests for pathological conditions during pregnancy.