Conservatively Managed Fetal Goiter: An Alternative to in utero Therapy

Abstract

Fetal goiter may arise from a variety of etiologies including iodine deficiency, overtreatment of maternal Graves' disease, inappropriate maternal thyroid replacement and, rarely, congenital hypothyroidism. Fetal goiter is often associated with a retroflexed neck and polyhydramnios, raising concerns regarding airway obstruction in such cases. Prior reports have advocated for cordocentesis and intra-amniotic thyroid hormone therapy in order to confirm the diagnosis of fetal thyroid dysfunction, reduce the size of the fetal goiter, reduce polyhydramnios, aid with the assistance of maternal thyroid hormone therapy and reduce fetal malpresentation. We report two cases of conservatively managed fetal goiter, one resulting in a vaginal delivery, and no evidence of postnatal respiratory distress despite the presence of polyhydramnios and a retroflexed neck on prenatal ultrasound.

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

“…Intrathyroidal arteriovenous shunting can cause high-output cardiac failure of the fetus and secondary hydrops [34]. In addition, neck hyperextension from the goiter preventing fetal head flexion could result in malpresentation during delivery and delivery dystocia [35, 36]. …”

Prenatal Diagnosis and Management of a Fetal Goiter Hypothyroidism due to Dyshormonogenesis

“…Multiple causes must be considered in fetal neck masses investigation, such as cystic hygroma, teratoma, angioma, lymphangioma, and goiter, among others. Thus, imaging exams like US and, when not well clarified, fetal MRI assume a relevant role in clarifying the underlying cause [1, 6, 7]. After the fetal goiter diagnosis, initial assessment should include maternal medication or supplementation, iodine status, thyroid function, and autoimmune thyroid disorders (TSH, fT3, fT4, anti-TPO, anti-TG, and TSH receptor blocking antibodies) [1, 7].…”

“…Amniocentesis is better accepted by parents when both methods are proposed to assess fetal thyroid status. However, experts have expressed some doubts about accuracy and correlation between thyroid hormonal levels in amniotic fluid and fetal hormonal status [1, 6, 7].…”

“…Some authors suggest in utero therapy only for situations of fetal goiter with progression or complications development such as polyhydramnios. Thus, slow-growing or stable goiters can be managed conservatively, with serial imaging follow-up, avoiding invasive intrauterine and repetitive procedures, due to inherent risks [6, 11].…”

“…The most common cause of CH is thyroid dysgenesis (agenesis, hypoplasia, or ectopy) and only 15-20% is due to specific errors in thyroid hormones synthesis-dyshormonogenesis, which is usually hereditary with autosomal recessive inheritance [2, 4]. Examples of these defects involve mutations in thyroid peroxidase (TPO), thyroglobulin (TG), sodium/iodide transporter, SLC26A4, DUOX2, DUOXA2, and DEHAL1 genes [5, 6].…”