Fetal thyroid disease due to maternal thyroid disorders Flashcards
Describe fetal hyperthyroidism.
Fetal hyperthyroidism occurs after week 25 of gestation due to transplacental transfer of TRAbs that stimulate the fetal thyroid. It can lead to complications such as IUGR, fetal goitre, tachycardia, and cardiac failure. The mother is usually given anti-thyroid drugs (ATDs) and the fetal heart rate, growth, and goitre size are monitored.
What is neonatal thyrotoxicosis?
Neonatal thyrotoxicosis is a condition that develops in 1% of infants born to thyrotoxic mothers. It is usually caused by the transplacental passage of stimulating TRAbs. Symptoms typically appear from 2 days after birth and the condition is transient, subsiding by 6 months. If left untreated, it can have a mortality rate of up to 30%. Treatment involves the use of ATDs and β-blockers.
Define fetal hypothyroidism.
Fetal hypothyroidism is a very rare occurrence that can happen when the mother has been treated with high doses of ATDs, typically over 30mg of carbimazole, with suppression of maternal FT4 levels. It is more likely to occur in the latter half of pregnancy. Fetal complications can include fetal bradycardia, fetal goitre, and abnormal skeletal and neurological development. Diagnosis can be confirmed using fetal cord blood from cordocentesis. Management involves monitoring by the pediatric team and treatment with levothyroxine if hypothyroidism persists.
Describe the management of fetal hyperthyroidism.
The management of fetal hyperthyroidism involves giving the mother anti-thyroid drugs (ATDs) and monitoring the fetal heart rate (aiming for less than 140bpm), growth, and goitre size. This condition occurs after week 25 of gestation due to the transplacental transfer of TRAbs that stimulate the fetal thyroid. Complications can include IUGR, fetal goitre, tachycardia, and cardiac failure.
What are the fetal complications of neonatal thyrotoxicosis?
Neonatal thyrotoxicosis can lead to fetal complications such as IUGR, fetal goitre, tachycardia, and cardiac failure. It develops in 1% of infants born to thyrotoxic mothers due to the transplacental passage of stimulating TRAbs. Symptoms usually appear from 2 days after birth and the condition is transient, subsiding by 6 months. Treatment involves the use of anti-thyroid drugs (ATDs) and β-blockers.
How is fetal hypothyroidism diagnosed?
Fetal hypothyroidism can be diagnosed by confirming hypothyroidism using fetal cord blood obtained from cordocentesis. This condition is a rare occurrence that can happen when the mother has been treated with high doses of anti-thyroid drugs (ATDs), typically over 30mg of carbimazole, with suppression of maternal FT4 levels. Fetal complications can include fetal bradycardia, fetal goitre, and abnormal skeletal and neurological development.
What should be measured in the 1st trimester for women with previous or current Graves’ disease?
All women with previous or current Graves’ disease should have thyroid receptor antibodies (TRAbs) measured in the 1st trimester to identify at-risk pregnancies. This is important because fetal thyroid disease due to maternal thyroid disorders can occur after week 25 of gestation due to the transplacental transfer of TRAbs that stimulate the fetal thyroid.
What is the treatment for neonatal thyrotoxicosis?
The treatment for neonatal thyrotoxicosis involves the use of anti-thyroid drugs (ATDs) and β-blockers. Neonatal thyrotoxicosis develops in 1% of infants born to thyrotoxic mothers due to the transplacental passage of stimulating TRAbs. Symptoms usually appear from 2 days after birth and the condition is transient, subsiding by 6 months. If left untreated, it can have a mortality rate of up to 30%.
Describe the fetal complications of fetal hypothyroidism.
Fetal hypothyroidism, which is a rare occurrence following treatment of the mother with high doses of anti-thyroid drugs (ATDs), can lead to fetal complications such as fetal bradycardia, fetal goitre, and abnormal skeletal and neurological development. Diagnosis can be confirmed using fetal cord blood obtained from cordocentesis. Cases are monitored by the pediatric team and treated with levothyroxine if hypothyroidism persists.
What is the significance of high levels of maternal TRAbs in the 2nd and 3rd trimesters?
High levels of maternal thyroid receptor antibodies (TRAbs) in the 2nd and 3rd trimesters are associated with the development of neonatal thyrotoxicosis. Neonatal thyrotoxicosis occurs in 1% of infants born to thyrotoxic mothers due to the transplacental passage of stimulating TRAbs. Symptoms usually appear from 2 days after birth and the condition is transient, subsiding by 6 months. Treatment involves the use of anti-thyroid drugs (ATDs) and β-blockers.
