Excessive prenatal supplementation of iodine and fetal goiter: report of two cases using three-dimensional ultrasound and magnetic resonance imaging / Suplementação pré-natal excessiva de iodo e bócio fetal: Relato de dois casos utilizando ultrassonografia tridimensional e ressonância magnética

Abstract Fetal thyroid complications in pregnancy are uncommon, and are commonly related to the passage of substances through the placenta. The excessive iodine intake during the pregnancy is a well-known mechanism of fetal thyroid enlargement or goiter, and invasive procedures have been proposed for the treatment of fetal thyroid pathologies. In the present report, we demonstrate two cases from different centers of prenatal diagnosis of fetal thyroid enlargement and/or goiter in three fetuses (one pair of twins, wherein both fetuses were affected, and one singleton pregnancy). The anamnesis revealed the ingestion of iodine by the patients, prescribed from inadequate vitamin supplementation. In both cases, the cessation of iodine supplement intake resulted in a marked reduction of the volume of the fetal thyroid glands, demonstrating that conservative treatmentmay be an option in those cases. Also, clinicians must be aware that patients may be exposed to harmful dosages or substances during pregnancy.

Resumo As complicações fetais da tireoide na gravidez são incomuns e são comumente relacionadas à passagem de substâncias pela placenta. A ingestão excessiva de iodo durante a gravidez é um mecanismo bem conhecido de aumento da tireoide ou bócio fetal, e procedimentos invasivos foram propostos para o tratamento de patologias da tireoide fetal. No presente relato de caso, demonstramos dois casos de diferentes centros de diagnóstico pré-natal de aumento da tireoide fetal e/ou bócio em três fetos (um par de gêmeos, em que ambos os fetos foram afetados, e uma gravidez única). A anamnese revelou a ingestão de iodo pelos pacientes prescrita por suplementação inadequada de vitaminas. Nos dois casos, a interrupção da ingestão de suplemento de iodo resultou em uma redução acentuada do volume das glândulas tireoides fetais, demonstrando que o tratamento conservador pode ser uma opção nestes casos. Além disso, os médicos devem estar cientes de que as pacientes podem ser expostas a doses ou substâncias nocivas durante a gravidez.

A Case of Intrauterine Thyroxine Therapy for Fetal Goitrous Hypothyroidsm / 대한주산의학회잡지

A 28-year-old primi gravida visited our department at 20 weeks gestation. The ultrasound screening revealed twin gestation, and follow up screening revealed a bilobed large fetal neck mass in the 1st twin. We measured thyroid volume with ultrasound which was 5.072 cm3. Other fetal organs appeared normal. Cordocentesis was performed for fetal thyroid function and congenital hypothyroidism was confirmed. In addition, maternal thyroid hormones were checked. The other fetus was normal. Thyroid stimulating hormone (TSH) in the maternal serum was increased, but thyroxine (T3) was (within normal range). Two weeks later, we checked TSH and free T4 in amniotic fluid and administered intra-amniotic thyroxine (200 ?g). We repeated the procedures 2 more times in two consecutive weeks. After 3 intra-amniotic thyroxine injection, follow-up cordocentesis revealed euthyroid status of the fetus. Although the thyroid gland had decreased in size and volume, it was still goitrous. At 36 weeks of gestation, the patient was admitted for preterm premature rupture of the membranes and the twin was delivered vaginally. The 1st twin was proved as an euthyroid status and antithyroid antibody was not detected. During the 3 years follow up, the baby had no considerable developmental problem. 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.

A Case of Prenatal Diagnosis of Congenital Fetal Goiter in Hyperthyroidism Mother / 대한주산의학회잡지

We report a case of prenatal diagnosis of fetal congenital goiter at 31weeks of gestation by ultrasonogram and fetal hypothyroidism confirmed at birth as thyroid function test by umbilical cord blood sampling. Maternal Graves' disease and the drugs used to treat hyperthyroidism in pregnant women can affect the fetus, causing hyperthyroidism or hypothyroidism and goiter. Fetal hypothyroidism may be caused by transplacental passage of either maternal thyrotropic-binding inhibitory immunoglobulin(TBII) antibodies or maternal treatment with propylthiouracil(PTU). Untreated fetal hypothyroidism may result in mental retardation, perceptual-motor, visual-spatial, and language developmental problems. In this article fetal thyroid function was not assessed by cordocentesis, but fetal congenital goiter was detected ultrasound. Ultrasound should be used to detect fetal goiter from 20 weeks onward. Fetal goiter should resolve when maternal PTU treatment is decreased. We have diagnosed fetal hypothyroidism in utero by ultrasonography. Significance of in utero management of fetal hypothyroidism is discussed.