Acquired neonatal thyroid disease due to TSH receptor antibodies in breast milk

Antibodies against thyroid-stimulating hormone receptor cause maternal-neonatal transmission of Graves' Disease

The present study aimed to investigate whether the thyroid-stimulating hormone receptor (TSHR) autoantibodies (Ab) from mothers with Graves' disease (GD) could cause neonatal thyroid disease and the underlying mechanisms of this. An adenovirus expressing the TSHR A-subunit and a control adenovirus expressing β-galactosidase was constructed by Beijing Sino Geno Max Co., Ltd. The sequences were subsequently verified and amplified via PCR. A GD model was established in female BALB/c mice (n=90) by three intramuscular injections of a TSHR-expressing adenovirus (Ad-TSHR). Mice injected with Ad-β-galactosidase served as a sham immunization group. The immunized females were paired with unimmunized males to generate offspring. The serum levels of TSHR-Ab and thyroxine (T4) of mothers and neonates were measured after delivery. Breast milk was collected from the stomachs of neonatal mice to determine the TSHR-Ab levels. The positive rate of serum TSHR-Ab (>0.3 IU/l) in the TSHR group was 99% (89/90) and 0% in the sham group. The mother mice in the TSHR group had elevated serum T4 levels and the thyroid pathological features of Graves' hyperthyroidism.GD mice gave birth to smaller newborns with thyroid pathological changes and higher serum levels of TSHR-Ab and T4, compared to the offspring in the sham group. The TSHR-Ab levels in breast milk from the GD mice declined with time. Mice immunized with Ad-TSHR exhibited the clinicopathological features of human GD and give birth to neonates with thyroid disease at birth.

Follow-up of infants born to mothers with Graves' disease

INTRODUCTION

The prevalence of neonatal hyperthyroidism (HN) due to maternal Graves Disease (GD) ranges from 0.1 to 2.7%. It may occur in pregnant women with the following: active DG, after treatment with radioactive iodine, anti-thyroid or thyroidectomy or with a previous child with hyperthyroidism. The aim of our observational study was to evaluate the follow-up of infants born to mothers with GD at a Tertiary Hospital prior to the implementation of a follow-up protocol.

METHODS

This was a retrospective observational study using data from the medical records of mothers with a diagnosis of GD and their newborns from January 2013 until May 2018. Newborns were divided into two groups: high and low risk for NH according to maternal TRAb, third trimester treatment and signs of fetal hyperthyroidism.

RESULTS

We identified 31 newborns, 58% female; 87% high risk. In none of the newborns was umbilical cord blood collected. In the high risk group, 22% had thyroid function evaluation at day-1, one patient presented with hyperthyroidism and 82% were asymptomatic. Considering the cases with an insufficient blood sample for analysis, 9 consultations would have been spared. We found a significant delay in obtaining the high-risk group results which would have spared 10 appointments. A positive correlation was found between age at outpatient clinic discharge and the number of appointments and the maternal TRAb titer.

CONCLUSION

The correct surveillance of pregnancy and newborns with identification of those at high risk is essential to avoid unnecessary consultations and blood analyses that increase parental anxiety and hospital costs. Consequently, a multidisciplinary protocol was created to standardize the approach.

Follow-up of infants born to mothers with Graves' disease

INTRODUCTION

The prevalence of neonatal hyperthyroidism (HN) due to maternal Graves Disease (GD) ranges from 0.1 to 2.7%. It may occur in pregnant women with the following: active DG, after treatment with radioactive iodine, anti-thyroid or thyroidectomy or with a previous child with hyperthyroidism. The aim of our observational study was to evaluate the follow-up of infants born to mothers with GD at a Tertiary Hospital prior to the implementation of a follow-up protocol.

METHODS

This was a retrospective observational study using data from the medical records of mothers with a diagnosis of GD and their newborns from January 2013 until May 2018. Newborns were divided into two groups: high and low risk for NH according to maternal TRAb, third trimester treatment and signs of fetal hyperthyroidism.

RESULTS

We identified 31 newborns, 58% female; 87% high risk. In none of the newborns was umbilical cord blood collected. In the high risk group, 22% had thyroid function evaluation at day-1, one patient presented with hyperthyroidism and 82% were asymptomatic. Considering the cases with an insufficient blood sample for analysis, 9 consultations would have been spared. We found a significant delay in obtaining the high-risk group results which would have spared 10 appointments. A positive correlation was found between age at outpatient clinic discharge and the number of appointments and the maternal TRAb titer.

CONCLUSION

The correct surveillance of pregnancy and newborns with identification of those at high risk is essential to avoid unnecessary consultations and blood analyses that increase parental anxiety and hospital costs. Consequently, a multidisciplinary protocol was created to standardize the approach.

Thyrotropic hormones

Thyroid hormones are crucial for normal cognition and neurodevelopment in children. The introduction of the screening programs for congenital hypothyroidism has decreased the incidence of untreated congenital hypothyroidism. As maternal thyroid disease is common, and may impact on thyroid gland development and function in the fetus, optimal management is crucial. This review discusses thyroid function and the impact of maternal thyroid disease on the fetus and neonate, as well as the influence of thyroid hormones, thyroid antibodies and the excretion of thyroid medication into breast milk on infant thyroid function.

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.

Congenital disorders of the thyroid: hypo/hyper

This article summarizes the ontogenesis and genetics of the thyroid with regards to its possible congenital dysfunction and briefly refers to the roles of the mother-placenta-fetal unit, iodine effect, and organic and functional changes of the negative feedback mechanism, as well as maturity and illness, in some forms of congenital hypo- and hyperthyroidism. This article also describes the published literature and the authors' data on the clinical aspects of congenital hypothyroidism, on the alternating hypo- and hyperthyroidism in the neonatal period, and on neonatal hyperthyroidism.

Management of neonatal endocrinopathies--best practice guidelines

Neonatal emergencies are uncommon, but may lead to significant morbidity and mortality if not recognised and managed promptly. Disorders of sex development, hypoglycaemia, thyrotoxicosis and calcium balance are discussed, with emphasis on the clinical assessment, investigations and management of these disorders in the acute setting.