Successful in utero treatment of fetal goiter and hypothyroidism

Perinatal airway management in neonatal goiter: A healthcare cost and utilization project (HCUP) kids' inpatient database analysis

INTRODUCTION

Fetal goiter is a rare congenital disorder that can present with life-threatening neonatal airway obstruction. Lifesaving and function-preserving airway management strategies are available, but routine delivery affords a limited window for intervention. Accordingly, fetal goiter is reported among the most common indications for ex-utero intrapartum treatment (EXIT). While EXIT prolongs the window for airway intervention to benefit the neonate, it elevates the risk to the pregnant person and requires extensive resources; therefore, data to guide ideal treatment selection are essential. This study aims to compare perinatal airway interventions between individuals with a birth hospitalization discharge diagnosis (BHDD) of goiter and the general population.

MATERIALS AND METHODS

Individuals with and without BHDD of goiter were identified in the Healthcare Cost and Utilization Project (HCUP) Kids' Inpatient Database from 2000 to 2019. The frequency of airway interventions on day of life (DOL) 0 or 1 were compared using the Rao-Scott chi-square test. Additionally, gestational age, type of intervention, complications, mortality, birth weight, and length of stay were examined for the goiter cohort.

RESULTS

Two-hundred eighty-seven weighted cases of goiter were identified in the study period. The population was 61 % male, 55 % White, and median birthweight was 3.3 kg. The median length of stay was 4.3 days, and average total charges were $42,332. Airway intervention on DOL 0 or 1 was performed in 16.9 % of individuals with goiter compared to 1.6 % in neonates without goiter (p < 0.001). Interventions in the goiter cohort included endotracheal intubation in 16 % of cases, laryngoscopy/bronchoscopy in 1-5% of cases, and tracheostomy in <1 % of cases. Fewer than 1 % of individuals undergoing intubation additionally had mass decompression/resection on DOL 0 or 1. No neonates received extracorporeal membrane oxygenation cannulation or cardiopulmonary resuscitation. Hypoxic encephalopathy occurred in <1 % of cases, among which endotracheal intubation was the only airway intervention performed. There were no mortalities among neonates with goiter.

CONCLUSION

Individuals with BHDD of goiter receive significantly higher rates of perinatal airway intervention. In most cases, endoscopic interventions alone were sufficient to avoid hypoxic neurological complications. These findings contribute to data to aid in clinical counseling and empower patients to make informed decisions according to their values and treatment goals.

Taking the Natural Exit: Opportunities for Treatment Rightsizing in Fetal Head and Neck Mass

Fetal head and neck masses, when present, may cause neonatal airway obstruction at birth and associated morbidity and mortality. Escalated maternal treatment intensity such as surgical laryngoscopist/airway surgeon attended delivery and ex utero intrapartum treatment can mitigate the neonatal risk, however, increase maternal risk for complications. Accordingly, accurate prediction of the potential neonatal benefit and maternal risk is essential. Serial third-trimester sonographic features suggestive of more severe airway obstruction may justify more aggressive intervention in the right patient. This case study presents a 23-year-old G1P0 with a fetus predicted to have reduced perinatal airway risk based upon serial third-trimester ultrasound findings. Treatment was de-escalated, and the patient was successfully managed. Collaborative data collection aimed at treatment rightsizing across neonatal, maternal, and systematic domains will support ideal allocation.

Fetal and Neonatal Thyroid Dysfunction

Fetal and neonatal dysfunctions include rare serious disorders involving abnormal thyroid function during the second half of gestation, which may persist throughout life, as for most congenital thyroid disorders, or be transient, resolving in the first few weeks of life, as in autoimmune hyperthyroidism or hypothyroidism and some cases of congenital hypothyroidism (CH) with the thyroid gland in situ. Primary CH is diagnosed by neonatal screening, which has been implemented for 40 years in developed countries and should be introduced worldwide, as early treatment prevents irreversible neurodevelopmental delay. Central CH is a rarer entity occurring mostly in association with multiple pituitary hormone deficiencies. Other rare disorders impair the action of thyroid hormones. Neonatal Graves' disease (GD) results from the passage of thyrotropin receptor antibodies (TRAbs) across the placenta, from mother to fetus. It may affect the fetuses and neonates of mothers with a history of current or past GD, but hyperthyroidism develops only in those with high levels of stimulatory TRAb activity. The presence of antibodies predominantly blocking thyroid-stimulating hormone receptors may result in transient hypothyroidism, possibly followed by neonatal hyperthyroidism, depending on the balance between the antibodies present. Antithyroid drugs taken by the mother cross the placenta, treating potential fetal hyperthyroidism, but they may also cause transient fetal and neonatal hypothyroidism. Early diagnosis and treatment are key to optimizing the child's prognosis. This review focuses on the diagnosis and management of these patients during the fetal and neonatal periods. It includes the description of a case of fetal and neonatal autoimmune hyperthyroidism.

Prenatal Gene Therapy

Prenatal gene therapy could provide a cure for many monogenic diseases. Prenatal gene therapy has multiple potential advantages over postnatal therapy, including treating before the onset of disease, the ability to induce tolerance and cross the blood-brain barrier. In this chapter, we will describe in utero gene therapy and its rationale, clinical trials of postnatal gene therapy, preclinical studies of in utero gene therapy, and potential risks to the mother and fetus.

Intra-amniotic levothyroxine infusions in a case of fetal goiter due to novel Thyroglobulin gene variants

Indications and administration of intra-amniotic infusions of L-thyroxine in the context of non-immune fetal hypothyroidism with goiter lack of standardization. Systematic follow-up of clinical features related to thyroid hormonal homeostasis may be useful to evaluate their efficiency and develop standardized management guidelines.

EXIT-to-airway: Fundamentals, prenatal work-up, and technical aspects

Ex-utero intrapartum treatment (EXIT) is a delivery strategy developed to manage a variety of prenatally diagnosed conditions in the transition to newborn life. This procedure allows control and provides time for intervention in otherwise life-threatening malformations, such as congenital upper airway obstructions. EXIT-to-airway has changed the outcome of fetuses with these anomalies. The main purpose of this intervention is to improve the safety of establishing a reliable airway at birth. Maximal but controlled uterine relaxation to maintain feto-maternal perfusion and thus gas exchange, while keeping the fetal and maternal well-being are the paradigms of any type of EXIT. The most important aspect of fetal airway management is to consolidate a highly trained, well-coordinated, multidisciplinary team that is prepared for every contingency. A comprehensive prenatal assessment, including ultrasound, fetal echocardiogram, fetal MRI, and genetic testing is imperative for patient selection. Extensive preoperative planning, ad-hoc team meetings, and surgical simulations for challenging cases are critical strategies to achieve the best outcomes. This article outlines the prenatal work-up, decision making, technical aspects, and principles for a successful EXIT-to-airway procedure.

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.

Thyroid hormone therapy in congenital hypothyroidism and pediatric hypothyroidism

The evaluation and management of hypothyroidism in children are similar to adults, but there are important differences based on the dependence on normal thyroid function for neurocognitive and physical development. In the pediatric population, hypothyroidism is frequently categorized as congenital or acquired hypothyroidism, depending on the age of presentation and the underlying etiology. The evaluation and management of children and adolescents with hypothyroidism are determined by the etiology as well as by the age at diagnosis, severity of the hypothyroidism, and the response to thyroid hormone replacement therapy. Children and adolescents require higher weight-based doses for thyroid hormone replacement than do adults, likely due to a shorter half-life of thyroxine (T4) and triiodothyronine (T3) in children, but weight-based dose requirements decrease as the child advances into adulthood. Multiple gaps in knowledge remains regarding how to optimize the treatment of hypothyroidism in pediatric patients, including (but not limited to) the selection of patients with subclinical hypothyroidism for treatment, and the potential benefit of combined LT3/LT4 therapy for patients with persistent symptoms and/or low T3 on LT4 monotherapy. The life-long impact on growth and development, and potentially on long-term cardiovascular and psychosocial health, are significant and highlight the importance of future prospective studies in pediatric patients to explore these areas of uncertainty.

Graves' disease complicated by fetal goitrous hypothyroidism treated with intra-amniotic administration of levothyroxine

Fetal goitrous hypothyroidism is a rare entity and is caused mainly by maternal treatment of Graves' disease (GD). We report a case of a 22-year-old woman referred at 12 weeks of gestation due to hyperthyroidism subsequent to recently diagnosed GD. She started treatment with propylthiouracil and, at 21 weeks of gestation, fetal goitre was detected. A cordocentesis confirmed the diagnosis of fetal goitrous hypothyroidism, and intra-amniotic administration of levothyroxine (LT4) was performed and repeated through the pregnancy due to maintenance of fetal goitre. The pregnancy proceeded without further complications and a healthy female infant was born at 37 weeks of gestation, with visible goitre and thyroid function within the normal range at birth. Although there is no consensus on the optimal dose, the number of injections and the interval between them, intra-amniotic LT4 administration is recommended once fetal goitrous hypothyroidism is suspected, in order to prevent long-term complications of fetal hypothyroidism.

Iodine-Induced Fetal Hypothyroidism: Diagnosis and Treatment with Intra-Amniotic Levothyroxine

BACKGROUND

Iodine is necessary for fetal thyroid development. Excess maternal intake of iodine can cause fetal hypothyroidism due to the inability to escape from the Wolff-Chaikoff effect in utero.

CASE REPORT

We report a case of fetal hypothyroid goiter secondary to inadvertent excess maternal iodine ingestion from infertility supplements. The fetus was successfully treated with intra-amniotic levothyroxine injections. Serial fetal blood sampling confirmed fetal escape from the Wolff-Chaikoff effect in the mid third trimester. Early hearing test and neurodevelopmental milestones were normal.

CONCLUSION

Intra-amniotic treatment of fetal hypothyroidism may decrease the rate of impaired neurodevelopment and sensorineural hearing loss.

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.

Graves' hyperthyroidism in pregnancy: a clinical review

Background

Graves’ hyperthyroidism affects 0.2% of pregnant women. Establishing the correct diagnosis and effectively managing Graves’ hyperthyroidism in pregnancy remains a challenge for physicians.

Main

The goal of this paper is to review the diagnosis and management of Graves’ hyperthyroidism in pregnancy. The paper will discuss preconception counseling, etiologies of hyperthyroidism, thyroid function testing, pregnancy-related complications, maternal management, including thyroid storm, anti-thyroid drugs and the complications for mother and fetus, fetal and neonatal thyroid function, neonatal management, and maternal post-partum management.

Conclusion

Establishing the diagnosis of Graves’ hyperthyroidism early, maintaining euthyroidism, and achieving a serum total T4 in the upper limit of normal throughout pregnancy is key to reducing the risk of maternal, fetal, and newborn complications. The key to a successful pregnancy begins with preconception counseling.

Intrauterine death following intraamniotic triiodothyronine and thyroxine therapy for fetal goitrous hypothyroidism associated with polyhydramnios and caused by a thyroglobulin mutation

In the absence of maternal thyroid disease or iodine deficiency, fetal goitre is rare and usually attributable to dyshormonogenesis, for which genetic ascertainment is not always undertaken in the UK. Mechanical complications include tracheal and oesophageal compression with resultant polyhydramnios, malpresentation at delivery and neonatal respiratory distress. We report an Indian kindred in which the proband (first-born son) had congenital hypothyroidism (CH) without obvious neonatal goitre. His mother’s second pregnancy was complicated by fetal hypothyroid goitre and polyhydramnios, prompting amniotic fluid drainage and intraamniotic therapy (with liothyronine, T3 and levothyroxine, T4). Sadly, intrauterine death occurred at 31 weeks. Genetic studies in the proband demonstrated compound heterozygous novel (c.5178delT, p.A1727Hfs*26) and previously described (c.7123G > A, p.G2375R) thyroglobulin (TG) mutations which are the likely cause of fetal goitre in the deceased sibling. TG mutations rarely cause fetal goitre, and management remains controversial due to the potential complications of intrauterine therapy however an amelioration in goitre size may be achieved with intraamniotic T4, and intraamniotic T3/T4 combination has achieved a favourable outcome in one case. A conservative approach, with surveillance, elective delivery and commencement of levothyroxine neonatally may also be justified, although intubation may be required post delivery for respiratory obstruction. Our observations highlight the lethality which may be associated with fetal goitre. Additionally, although this complication may recur in successive pregnancies, our case highlights the possibility of discordance for fetal goitre in siblings harbouring the same dyshormonogenesis-associated genetic mutations. Genetic ascertainment may facilitate prenatal diagnosis and assist management in familial cases.

Opposing Effects of Maternal Hypo- and Hyperthyroidism on the Stability of Thalamocortical Synapses in the Visual Cortex of Adult Offspring

Insufficient or excessive thyroid hormone (TH) levels during fetal development can cause long-term neurological and cognitive problems. Studies in animal models of perinatal hypo- and hyperthyroidism suggest that these problems may be a consequence of the formation of maladaptive circuitry in the cerebral cortex, which can persist into adulthood. Here we used mouse models of maternal hypo- and hyperthyroidism to investigate the long-term effects of altering thyroxine (T4) levels during pregnancy (corresponding to embryonic days 6.5-18.5) on thalamocortical (TC) axon dynamics in adult offspring. Because perinatal hypothyroidism has been linked to visual processing deficits in humans, we performed chronic two-photon imaging of TC axons and boutons in primary visual cortex (V1). We found that a decrease or increase in maternal serum T4 levels was associated with atypical steady-state dynamics of TC axons and boutons in V1 of adult offspring. Hypothyroid offspring exhibited axonal branch and bouton dynamics indicative of an abnormal increase in TC connectivity, whereas changes in hyperthyroid offspring were indicative of an abnormal decrease in TC connectivity. Collectively, our data suggest that alterations to prenatal T4 levels can cause long-term synaptic instability in TC circuits, which could impair early stages of visual processing.

Intra-amniotic thyroxine to treat fetal goiter

A 35-year-old pregnant woman visited our department and had been treated with 100 µg of daily oral levothyroxine for hypothyroidism. An ultrasonography screening was performed at 25 weeks gestation and revealed a fetal goiter and an increased amniotic fluid volume. Fetal hypothyroidism was confirmed by cordocentesis and amniotic hormone levels at 26 weeks gestation. We treated the mother with 200 µg of daily oral levothyroxine to optimize the transplacental transfer. A total of four intra-amniotic injections of levothyroxine were administered, resulting in progressive reduction in the fetal thyroid volume of goiter as measured by 3D ultrasonography and increased amniotic fluid volume. Following birth, neonatal serum thyroid stimulating hormone level was within the normal range, but free T4 was reduced. Based on this case, we suggest that monitoring amniotic fluid thyroid hormone concentration and intra-amniotic levothyroxine injection can be used to reduce the thyroid volume of goiters and to prevent polyhydramnios.

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.

Sequential Amniotic Fluid Thyroid Hormone Changes Correlate with Goiter Shrinkage following in utero Thyroxine Therapy

Several isolated reports of fetal goiter treatment have shown limited generalizability of approaches and provide no real guidance for optimal timing, dosages, and treatment strategies. Graves' disease accounts for >60% of these cases. Maternal treatments of hyperthyroidism include antithyroid medications such as methimazole and more commonly propylthiouracil (PTU). Here, our management of a patient with a fetal thyroid goiter from maternal exposure to PTU diagnosed at 23.6 weeks' gestation and the management of other cases allow us propose a general strategy for treatment. Intrauterine therapy with 200 and then 400 μg of levothyroxine (3 weeks apart) showed an 85% reduction in fetal thyroid goiter volume. We collected amniotic fluid samples at the time of treatments and assayed thyroid hormones and associated antibodies which closely reflected the changes in thyroid goiter mass volume. Our observations suggest a weekly or biweekly therapeutic intervention schedule. Utilizing both goiter size as well as a novel approach in using amniotic fluid hormone levels to monitor therapy efficacy might improve the quality of treatments. Only with a standardized approach and collection of amniotic fluid thyroid panels do we have the opportunity to develop the database required to determine the number and timing of treatments needed.

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.

Effectiveness of preoperative plasmapheresis in a pregnancy complicated by hyperthyroidism and anti-thyroid drug-associated angioedema

Hyperthyroidism is not a rare entity in pregnancy and 85% of these cases attributed to Graves' disease (GD). There is no therapeutic modality for GD considered as totally safe in pregnancy. Fetal and neonatal risks of maternal hyperthyroid disease are related to the hyperthyroidism itself and/or to the medical treatment of the disease. There are no data supporting an association between congenital anomalies in the fetus and propylthiouracil (PTU). Hepatotoxicity, cytopenias--especially agranulocytosis and quite rarely, angioedema, may be seen as side effects of PTU. In this case report, we examine an instance of Graves' hyperthyroidism diagnosed during pregnancy. In this case, a serious side effect during anti-thyroid drug usage was encountered, eventually resulting in surgery in the second trimester. This intervention was assisted by the use of plasmapheresis to obtain rapid normalization of serum thyroid hormone levels.

Two cases of fetal goiter

INTRODUCTION

Anterior fetal neck masses are rarely encountered. Careful routine ultrasound screening can reveal intrauterine fetal goiters (FGs). The incidence of goitrous hypothyroidism is 1 in 30,000-50,000 live births. The consequences of both FG and impaired thyroid function are serious.

AIMS AND OBJECTIVES

To emphasize role of ultrasound in both invasive and non-invasive management of FG.

MATERIALS AND METHODS

Two pregnant patients, during second trimester, underwent routine antenatal ultrasound revealing FG, were investigated and managed.

RESULTS

Case 1: Revealed FG with fetal hypothyroidism. Intra-amniotic injection l-thyroxine given. Follow-up ultrasound confirmed the reduction of the goiter size. At birth, thyroid dyshormogenesis was suspected and neonate discharged on 50 mcg levothyroxine/day with normal growth and development so far. Case 2: Hypothyroid mother with twin pregnancy revealed FG, in twin 1, confirmed on magnetic resonance imaging (1.5 × 1.63 cm). The other twin had no thyroid swelling. Cordocentesis confirmed hypothyroidism in twin 1. Maternal thyroxine dose increased as per biochemical parameters leading to reduction in FG size. Mother delivered preterm and none of the twins had thyroid swelling. Fetal euthyroidism was confirmed on biochemical screening.

CONCLUSION

FG during pregnancy should be thoroughly evaluated, diagnosed and immediately treated; although in utero options for fetal hypothyroidism management are available, emphasis should be laid on non-invasive procedures. Newer and better resolution techniques in ultrasonography are more specific and at the same time are less harmful.

Hyperthyroidism in pregnancy

PURPOSE OF REVIEW

Successful outcome in pregnancy hyperthyroidism depends on the cause, interpretation of laboratory tests, and careful use of antithyroid drug (ATD) therapy. Planning of a pregnancy in a woman with active or past history of Graves' hyperthyroidism is mandatory in order to avoid complications.

RECENT FINDINGS

Fetal health may be affected by three factors: poor control of maternal hyperthyroidism, titer of maternal TRAb, and inappropriate use of ATD. Careful assessment of thyroid function through pregnancy and evaluation of fetal development by ultrasonography is the cornerstone for a successful outcome. In a subgroup of women previously treated with ablation therapy, those whose serum TSRAb titers remained elevated, are at risk of having a fetus/neonate with Graves' hyperthyroidism. Use of ATD during lactation is well tolerated, if recommended guidelines are followed.

SUMMARY

Women during their childbearing age with active Graves' hyperthyroidism should plan their pregnancy. Causes of hyperthyroidism in pregnancy include Graves' disease or autonomous adenoma, and transient gestational thyrotoxicosis as a consequence of excessive production of human chroionic gonadotropin by the placenta. Careful interpretation of thyroid function tests and frequent adjustment of ATD is of utmost importance in the outcome of pregnancy. Graves' hyperthyroidism may relapse early in pregnancy or at the end of the first year postpartum.

Management of thyroid dysfunction during pregnancy and postpartum: an Endocrine Society clinical practice guideline

OBJECTIVE

The aim was to update the guidelines for the management of thyroid dysfunction during pregnancy and postpartum published previously in 2007. A summary of changes between the 2007 and 2012 version is identified in the Supplemental Data (published on The Endocrine Society's Journals Online web site at http://jcem.endojournals.org).

EVIDENCE

This evidence-based guideline was developed according to the U.S. Preventive Service Task Force, grading items level A, B, C, D, or I, on the basis of the strength of evidence and magnitude of net benefit (benefits minus harms) as well as the Grading of Recommendations, Assessment, Development, and Evaluation (GRADE) system to describe both the strength of recommendations and the quality of evidence.

CONSENSUS PROCESS

The guideline was developed through a series of e-mails, conference calls, and one face-to-face meeting. An initial draft was prepared by the Task Force, with the help of a medical writer, and reviewed and commented on by members of The Endocrine Society, Asia and Oceania Thyroid Association, and the Latin American Thyroid Society. A second draft was reviewed and approved by The Endocrine Society Council. At each stage of review, the Task Force received written comments and incorporated substantive changes.

CONCLUSIONS

Practice guidelines are presented for diagnosis and treatment of patients with thyroid-related medical issues just before and during pregnancy and in the postpartum interval. These include evidence-based approaches to assessing the cause of the condition, treating it, and managing hypothyroidism, hyperthyroidism, gestational hyperthyroidism, thyroid autoimmunity, thyroid tumors, iodine nutrition, postpartum thyroiditis, and screening for thyroid disease. Indications and side effects of therapeutic agents used in treatment are also presented.

Antithyroid drug-induced fetal goitrous hypothyroidism

Maternal overtreatment with antithyroid drugs can induce fetal goitrous hypothyroidism. This condition can have a critical effect on pregnancy outcome, as well as on fetal growth and neurological development. The purpose of this Review is to clarify if and how fetal goitrous hypothyroidism can be prevented, and how to react when prevention has failed. Understanding the importance of pregnancy-related changes in maternal thyroid status when treating a pregnant woman is crucial to preventing fetal goitrous hypothyroidism. Maternal levels of free T(4) are the most consistent indication of maternal and fetal thyroid status. In patients with fetal goitrous hypothyroidism, intra-amniotic levothyroxine injections improve fetal outcome. The best way to avoid maternal overtreatment with antithyroid drugs is to monitor closely the maternal thyroid status, especially estimates of free T(4) levels.

Fetal euthyroid goiter

We present a very unusual case of a baby born with antenatally diagnosed large neck swelling causing compression of trachea on imaging, who was euthyroid. There was no history of any thyroid disease in the mother and no history of exposure to known goitrogens. The goiter gradually reduced in size and baby's thyroid function as well as neurodevelopment remained completely normal during follow-up.

Fetal and neonatal Graves disease: a case report and review of the literature

Fetal and neonatal thyrotoxicosis from maternal Graves disease is a very rare entity. Fetal symptoms result from the transplacental passage of thyroid-stimulating immunoglobulins, which persist in the neonate resulting in neonatal symptoms. We present a case of fetal and neonatal thyrotoxicosis from maternal Graves disease. Fetal symptoms were controlled with maternal administration of antithyroid drugs leading to fetal thyroid inhibition. We present this case with a brief review of the literature.

Treating fetal thyroid and adrenal disorders through the mother

Advances in imaging techniques and in molecular diagnosis have enabled the identification in the fetus of disorders of thyroid and adrenal function that can potentially be treated in utero through the mother. In women with Graves disease, the rare instances of autoimmune fetal hyperthyroidism can generally be treated in a noninvasive way by optimizing treatment of the mother. For fetal hypothyroidism with goiter leading to hydramnios, repeated intra-amniotic injections of thyroxine have been reported to decrease the size of the fetal thyroid, but experience is limited and the risk of premature labor is raised. In women who have previously borne a child with severe congenital adrenal hyperplasia, attempts to prevent virilization of the external genitalia of further affected female fetuses involves treatment with high doses of dexamethasone from week 7 of gestation to term, which includes the crucial period of organogenesis. Only one of every eight fetuses treated will, however, benefit from this therapy, meaning that seven are unnecessarily exposed to this potentially harmful agent. In this article, we review the rationale and evidence for efficacy of these approaches, and discuss their potential adverse effects as well as the ethical problems that they raise.

Successful intrauterine therapy for fetal goitrous hypothyroidism during late gestation

We experienced a case of fetal goitrous hypothyroidism in an infant delivered by a 33-year-old woman receiving 300 mg/day of propylthiouracil (PTU) for hyperthyroidism due to Graves' disease. A large fetal goiter (maximum diameter, 60 mm) was detected by magnetic resonance imaging (MRI) at 36 weeks of gestation. Initial fetal blood sampling revealed hypothyroidism with a serum thyroid-stimulating hormone (TSH) of 99 microIU/mL, free triiodothyronine (T(3)) of 1.97 pg/mL, and free thyroxine (T(4)) of 0.29 ng/dL. Consequently, a diagnosis of fetal goitrous hypothyroidism due to transplacental passage of maternal PTU was made. To reduce the risk of perinatal complications, 300 microg of levothyroxine sodium (L-T(4)) was administered into the maternal amniotic fluid twice between 37 and 38 weeks of gestation. Subsequent fetal MRI showed that the size of goiter had decreased. At 38 weeks and 5 days of gestation, a 3042-g male infant was born by cesarean section. There were no severe complications at delivery, although mild tachypnea was observed and the infant's thyroid gland was slightly enlarged. He was treated with L-T(4) for two weeks. At present, his growth and neurological development are normal. This case indicates that intrauterine therapy by the intraamniotic administration of L-T(4) can be effective in treating fetal goitrous hypothyroidism even during late gestation.

Hyperthyroidism

Thyrotoxicosis is a condition resulting from elevated levels of thyroid hormone. In this article, the authors review the presentation, diagnosis, and management of various causes of thyrotoxicosis.

Therapy Insight: management of Graves' disease during pregnancy

The diagnosis of Graves' disease in pregnancy can be complex because of normal gravid physiologic changes in thyroid hormone metabolism. Mothers with active Graves' disease should be treated with antithyroid drugs, which impact both maternal and fetal thyroid function. Optimally, the lowest possible dose should be used to maintain maternal free thyroxine levels at or just above the upper limit of the normal nonpregnant reference range. Fetal thyroid function depends on the balance between the transplacental passage of thyroid-stimulating maternal antibodies and thyroid-inhibiting antithyroid drugs. Elevated levels of serum maternal anti-TSH-receptor antibodies early in the third trimester are a risk factor for fetal hyperthyroidism and should prompt evaluation of the fetal thyroid by ultrasound, even in women with previously ablated Graves' disease. Maternal antithyroid medication can be modulated to treat fetal hyperthyroidism. Serum TSH and either total or free thyroxine levels should be measured in fetal cord blood at delivery in women with active Graves' disease, and those with a history of (131)I-mediated thyroid ablation or thyroidectomy who have anti-TSH-receptor antibodies. Neonatal thyrotoxicosis can occur in the first few days of life after clearance of maternal antithyroid drug, and can last for several months, until maternal antibodies are also cleared.

Successful in utero treatment of fetal goitrous hypothyroidism: case report and review of the literature

In this report, we present a case of fetal goiter with overdistended fetal neck and mild polyhydramnios. Amniocentesis and cordocentesis were conducted at 32 weeks' gestation and fetal goitrous hypothyroidism was diagnosed. Intra-amniotic injection of l-thyroxine (T4) was performed with a weekly dose of 150 microg four times between 33 and 36 weeks' gestation. In response to this in utero treatment, the goiter was reduced and polyhydramnios was improved. The mother gave birth to a healthy live male infant with normal thyroid function. From our case report and review of previous literature, we recommend that the amount of l-thyroxine start as low as 150 microg, and that repeat cordocentesis be avoided as long as other clinical and laboratory parameters indicate improvement of the fetal conditions.

Intrauterine diagnosis and management of fetal goitrous hypothyroidism: a report of an Iranian family with three consecutive pregnancies complicated by fetal goiter

The diagnosis and treatment of hypothyroidism during the fetal period may decrease perinatal morbidity and are believed to be important to optimize growth and intellectual development. Herewith a case report of fetal goitrous hypothyroidism is presented in a euthyroid mother, detected at 34 weeks' gestation by ultrasonography, and treated with intra-amniotic levothyroxine injections. The mother had two previous consecutive pregnancies (13 and 8 years ago), also complicated by the occurrence of fetal goiter, resulting in tracheal compression, asphyxia, and early neonatal death in the first and in an emergency cesarean section delivery, because of fetal malpresentation, in the second neonate affected by congenital hypothyroidism (CH). The present male newborn, although born without observable goiter, had a large thyroid on ultrasonography and an early rise of his peripheral venous blood thyrotropin confirmed the diagnosis of CH. Low serum thyroglobulin in the proband and his older brother and parental consanguinity was mostly compatible with a thyroglobulin defective synthesis and secretion as the cause of CH and fetal goiter. Despite apparently sufficient dose of intraamniotic levothyroxine injections repeated weekly from 34-37 weeks' gestation (i.e., four injections of 500 microg levothyroxine), neonatal bone age on the second day of life showed delayed skeletal maturation.

Non-invasive management of fetal goiter during maternal treatment of hyperthyroidism in Grave's disease

There is an increased risk of fetal goiter in patients who have a history of Grave's disease and undergo propylthiouracil (PTU) treatment during pregnancy. In this report, we describe a case of a fetal goiter detected by antenatal ultrasound at the 26th week of gestation in a mother treated with PTU for Grave's disease. A 32 x 38 x 20 mm fetal goiter was detected, each lobe measured 30 x 18 x 18 mm and estimated volume was 10 cm3. Subsequently, fetal thyroid function was assessed by umbilical fetal blood sampling. Cord blood showed elevated serum TSH (40.2 mU/l) and normal concentrations of free T4 (9.5 pmol/l) and free T3 (2.6 pmol/l). There were no other ultrasonographic signs of fetal hypothyroidism. Based on the above findings, the mother's PTU dosage was reduced to 50 mg daily from a total of 150 mg and weekly ultrasonographic examinations were performed. Six weeks after the initial ultrasound, a complete regression of the fetal goiter was noted. At the 34th week of gestation, the patient was delivered due to intrauterine growth restriction and oligohydramnios and gave birth to a male, weighing 1,920 g. The newborn thyroid was not palpable and thyroid ultrasonography was normal. Cord blood TSH was normal (8.4 mU/l) and free T4 was within lower normal limit (9.03 pmol/l). Ten days later, newborn thyroid function was normal and the baby did well afterwards. In conclusion, after the evaluation of fetal thyroid status, selected cases with fetal goiter can be initially managed without intrauterine treatment.

Thyroid disorders and pregnancy

During pregnancy physiologic changes in thyroid function occur which should not be misinterpreted as pathological. Thyroid disorders may complicate pregnancy and need thorough investigation and treatment in order to ensure a favourable pregnancy outcome. The incidence of hyperthyroidism in pregnant women has been reported to be approximately 0.2%. The leading cause is Graves' disease. Treatment of hyperthyroidism includes antithyroid drugs or surgery to avoid adverse effects on the neonate such as prematurity, intrauterine growth retardation and fetal or neonatal thyrotoxicosis. Use of radioactive iodine is contraindicated. Hypothyroidism during pregnancy is associated with gestational hypertension and low birth weight. Women on thyroid replacement therapy before pregnancy may require an increase in dosage during pregnancy. Pregnant women with chronic autoimmune thyroiditis have a higher incidence of spontaneous miscarriage. Nodular disease demands meticulous investigation to rule out a toxic adenoma or malignancy. Surgery in the case of cancer can be postponed under certain circumstances. Within one year following delivery, about 5-10% of women may exhibit postpartum autoimmune thyroid dysfunction, which may result in hypothyroidism.

Autoimmune thyroid disease in pregnant women and their offspring

OBJECTIVE

To present an overview of autoimmune thyroid disease (AITD) that can occur in pregnancy.

METHODS

The major thyroid antibodies that can traverse the maternal-fetal circulation and affect the fetus are summarized, those women at risk of having affected fetuses are identified, and the diagnosis, course, and treatment of AITD in maternal and neonatal patients are discussed.

SUMMARY

AITD, including Graves' disease and autoimmune thyroiditis, is common in women of childbearing age. Rarely, the fetus can be affected because of transplacental passage of maternal IgG. Of the thyroid autoantibodies found in AITD, only those directed against the thyroid-stimulating hormone (TSH) receptor have been shown to cause fetal thyroid dysfunction. Both transient neonatal hyperthyroidism and hypothyroidism have been described, as has delayed onset of neonatal hyperthyroidism due to the coexistence of stimulating and blocking TSH receptor antibodies. In general, affected infants are those born to mothers with the most potent antibody activity, and the duration of the neonatal thyroid dysfunction is dependent on the antibody titer and the rate of metabolic clearance from the infant's circulation. If fetal hyperthyroidism is suspected, maternal TSH receptor antibodies should be measured during the third trimester of pregnancy. For neonatal hypothyroidism, this measurement in the mother or baby soon after birth will suffice. Screening for the presence of TSH receptor antibodies by radioreceptor assay is the most cost-effective approach. If results are positive, bioassay should be done to determine the nature of the antibody activity. Women at risk of having babies with neonatal hyperthyroidism include those with a history of previous affected infants, with difficult to control thyrotoxicosis, or with a history of Graves' disease and development of hypothyroidism either spontaneously or as a result of thyroid gland ablation. Transient neonatal hypothyroidism due to TSH receptor-blocking antibodies should be suspected in any infant with hypothyroidism born to a mother with AITD (particularly those with previously affected offspring).

CONCLUSION

Treatment of maternal hyperthyroidism must consider both maternal and fetal thyroid status. In general, the lowest dose of antithyroid medication sufficient to produce maternal euthyroidism or slight hyperthyroidism is used. In pregnant women with hypothyroidism, doses of L-thyroxine should be sufficient to normalize maternal thyroid function without regard to the fetus. Identification and treatment of affected infants soon after birth will ensure a normal outcome. Whether inadequately treated maternal hypothyroidism is associated with a permanent intellectual deficit in the offspring is currently unknown.

Serial in utero ultrasonographic measurements of the fetal thyroid: a new complementary tool in the management of maternal hyperthyroidism in pregnancy

OBJECTIVE

Treatment of maternal hyperthyroidism during pregnancy is complicated by the lack of readily available measures of the thyroid status of the fetus. The aim of this study is to describe the use of serial in utero ultrasound measurements of fetal thyroid in patients being treated for Graves' disease in pregnancy.

METHODS

Over a 24-month period, all pregnant women with Graves' disease attending our special Fetal Thyroid Unit were followed. Maternal thyroid status was assessed by thyroid function tests. Fetal thyroid size was measured serially by transvaginal ultrasonography between 14 and 17 weeks of gestation and by abdominal ultrasonography between 18 and 37 weeks of gestation in 20 women with Grave's disease.

RESULTS

In 15 fetuses, thyroid width and circumference were within the 95% confidence interval of the normal population. In five fetuses, thyroid size was above the 95th percentile for gestational age. In three of them, thyroid size decreased concurrently with a decrease in maternal thionamide dosage, reaching normal range. These three fetuses were born euthyroid. In two fetuses, thyroid size was unaffected by a decrement in maternal drug dosage. Both had neonatal thyrotoxicosis at birth.

CONCLUSIONS

Serial in utero ultrasonography measuring fetal thyroid size in mothers with Graves' disease can serve as an effective noninvasive tool for the early detection of enlarged fetal thyroid. These findings can be used to monitor the maternal antithyroid drug dosage, thereby preventing intrauterine hypothyroidism in some cases. When a dosage reduction does not cause a decrease in fetal thyroid size, transplacental passage of thyroid-stimulating antibodies causing fetal thyrotoxicosis should be suspected.

Graves' disease in pregnancy: prospective evaluation of a selective invasive treatment protocol

OBJECTIVE

Graves' disease in pregnancy carries a risk of fetal thyrotoxicosis from the transplacental transfer of thyroid-stimulating antibodies or fetal hypothyroidism from transplacental transfer of antithyroid drugs and thyroid-blocking antibodies.

STUDY DESIGN

From 1991 through 2002, all pregnant women with Graves' disease underwent follow-up evaluations that included serial thyroid-stimulating antibody level, thyroid function, and ultrasound examinations. Umbilical blood sampling was recommended if the thyroid-stimulating antibody level was abnormally high or if fetal tachycardia, goiter, intrauterine growth retardation, or hydrops were present. For fetal hyperthyroidism, the mother received antithyroid drugs; for fetal hypothyroidism, maternal antithyroid treatment was reduced, and thyroxine was injected into the amniotic sac.

RESULTS

Of 40000 deliveries, 24 pregnancies (26 fetuses) occurred in 18 women with Graves' disease. Nine of 14 mothers with positive findings elected umbilical blood sampling. In 4 of the mothers, the results were normal. Hyperthyroidism and hypothyroidism were diagnosed in 2 and 3 fetuses, respectively. All the fetuses were treated successfully by the protocol with up to four repeated umbilical blood samplings. No complications were recorded in any of the 20 umbilical blood sampling. In the 5 patients who had only elevated thyroid-stimulating antibody levels and who did not elect umbilical blood sampling, sonographic findings remained normal up to term, and the newborn infants were normal. One of 12 children (in whose case we did not recommend umbilical blood sampling) was born with transient hypothyroidism caused by maternal propylthiouracil treatment. All children, whose cases were followed for up to 9 years, are normal.

CONCLUSION

In women with Graves' disease, umbilical blood sampling in selected cases may improve the control of fetal thyroid function.

Fetal pharmacotherapy

Rapid progress has recently been encountered in pharmacologically treating the unborn baby. This unique area of drug therapy raises new methodological and ethical questions. This article is a systematic review of known modalities of fetal pharmacotherapy, and aims to highlight essential principles, difficulties and controversies in fetal pharmacotherapy. Unique pharmacokinetic features of pregnancy, the placenta and the fetus govern maternal-to-fetal drug transfer. Ethically, it is important that the mother and family are appropriately informed about the evidence in favour of specific fetal therapy, its risks and alternatives. Antenatal use of corticosteroids for lung maturation is an example of adequate methodology, leading to clear results. In contrast, the initial hopes in antenatal use of phenobarbital were based on less than optimal methodology. Folic acid for the prevention of neural tube defects is the first instance of fetal therapy that has led to the prevention of a major malformation. Serious infections, such as HIV, Group B streptococcus and toxoplasmosis highlight the need for controlled, randomised studies to prevent fetal infection. With scores of new modalities of fetal therapy likely to be introduced in the next few years, it will be important to adhere to the best possible methodology and execution, in order to address optimally the needs of the fetus.

Intrauterine diagnosis and management of congenital goitrous hypothyroidism

The intrauterine recognition and treatment of congenital goitrous hypothyroidism may not only reduce the obstetric complications associated with large goiters, but possibly improve the prognosis for normal growth and mental development of affected fetuses. We present a case of fetal goiter diagnosed at 29 weeks of gestation following routine ultrasound examination. Fetal blood sampling performed at this time confirmed the presence of fetal hypothyroidism. Treatment was performed using a series of intra-amniotic injections between 31 and 36 weeks, initially with tri-iodothyronine (T3) and subsequently with thyroxine. During this period, shrinkage of the fetal goiter, increasing neck flexion and resolution of the polyhydramnios was observed. Following birth, neonatal serum thyroid-stimulating hormone levels were within the normal range but thyroxine was reduced. The baby was started on daily oral thyroxine and, on examination 7 weeks following birth, he appeared clinically and chemically euthyroid. In the absence of maternal thyroid disease, fetal goiter is extremely rare, with only seven cases previously reported in the English literature to have used intra-amniotic thyroxine injections as a form of treatment. This report reviews the current literature regarding the diagnosis and intrauterine management of fetal goiter and considers the possibility of T3 therapy in future cases of congenital hypothyroidism.

Antenatal diagnosis and treatment of a case of fetal goitrous hypothyroidism associated with high-output cardiac failure

A case of fetal goitrous hypothyroidism associated with high-output cardiac failure is presented. At 32 weeks of gestation, the antenatal diagnosis of goiter was made based on ultrasound examination, and the fetal thyroid function was examined by amniocentesis and cordocentesis. Color and pulsed Doppler examinations demonstrated a high vascular flow pattern in the goiter and marked elevation of the maximum velocity in the common carotid artery at the level of the neck. It was suspected that arteriovenous shunting through the large goiter resulted in high-output cardiac failure with cardiomegaly and pleural effusion. The fetus was treated by injection of levothyroxine sodium into the amniotic fluid at 33 weeks of gestation and the goiter thereafter decreased in size, with subsequent improvement of the high-output cardiac failure. The maximum velocity in the common carotid artery fell rapidly before the shrinkage of the fetal goiter and in parallel with the fetal level of thyroid stimulating hormone.

Biochemical investigation of foetal and neonatal thyroid function using the ACS-180SE analyser: clinical application

Despite sonographic detection of foetal goitre, uncertainty persists in the initial diagnosis of thyrotoxicosis and hypothyroidism. The aim of this study was to establish foetal and neonatal iodothyronine and thyrotrophin reference values for the ACS-180SE analyser. From 22 to 36 weeks of gestation, median foetal serum free thyroxine (FT4) levels increased from 6.0 pmol/L to 143 pmol/L, while free tri-iodothyronine (FT3) levels increased from 0.7 pmol/L to 1.9 pmol/L and mean thyrotrophin (TSH) levels remained stable (10.2 +/- 3.8mU/L; n = 33). At birth, concentrations were independent of gender and gestational age. Among the 10 cases of sonographically detected foetal goitre, serum TSH and FT4 were measured in five, showing hypothyroidism (3/5) or hyperthyroidism (2/5). Cord blood TSH levels reflected the efficacy of prenatal therapy. Measurement of foetal FT4 and TSH can be used to confirm foetal thyroid dysfunction, whereas treatment efficacy can be assessed sonographically and confirmed by measurement of TSH assay at birth.

Iodine kinetics and effectiveness of stable iodine prophylaxis after intake of radioactive iodine: a review

Ingestion of potassium iodide (KI) offers effective protection against irradiation of the thyroid after accidental exposure to radioactive iodine. This prophylaxis aims at rapidly obtaining maximal thyroid protection without adverse effects. This article reviews studies on iodine kinetics in humans and on the efficacy of KI in protecting the thyroid. In adults with normal thyroid function, ingestion of 100 mg of iodide just before exposure to radioactive iodine blocks at least 95% of the thyroid dose. If exposure persists after iodide ingestion (100 mg), the percentage of averted dose may decrease significantly. Daily ingestion of a dose of 15 mg of KI would then maintain the thyroid blockade at a level above 90%. The efficacy of iodide and the occurrence of antithyroid effects also depend on external and individual factors such as dietary iodine intake, thyroid function, and age. The KI dosage regimen should be adjusted for age at exposure. For the fetus, the newborn, children, and adolescents, the risk of radiation-induced thyroid cancer in case of accidental exposure to radioactive iodine justifies KI prophylaxis, despite the risk of hypothyroidism, especially in newborns. For the elderly, the benefits of KI may be lower than the risk of iodine-induced hyperthyroidism.