[Diagnosis and therapy of fetal thyroid gland dysfunction in primary maternal disease]

Fetal and maternal thyroid function are working independently under physiologic conditions. In case of maternal autoimmune hyperthyroidism during pregnancy there is an up to 12% chance for the fetus to develop thyroid dysfunction, mediated by the transplacental passage of maternal immunoglobulins directed against TSH receptors in the fetal thyroid gland. This may lead to intrauterine growth retardation, craniosynostosis, preterm delivery, perinatal death, etc. Sonography and fetal blood sampling provide important information to detect fetuses at risk and allow intrauterine therapy. Furthermore prenatal diagnosis is important in case of maternal antithyroid drug ingestion possibly leading to fetal hypothyroidism and goitre. The cooperation of specialists for internal and fetal medicine is required for the management of maternal thyroid disease in pregnancy.