Diagnosis and Successful Intrauterine Treatment of Fetal Goiter: A Case Report

The intrauterine diagnosis and treatment of fetal goitrous hypothyroidism are important not only to reduce the obstetric complications but also to optimize growth and intellectual development in affected fetuses reducing probably some development delays in visual-spatial, perceptual-motor and language abilities as reported in literature. We present a case of fetal goiter born of a 31 year old primigravida with hyperthyroidism diagnosed in the first trimester of pregnancy and treated with propylthiouracile (PTU) 150 mg/day from 15 weeks of gestation. Fetal goiter and polyhydramnios were identified sonographically at 22 weeks, and PTU was decreased to 50 mg/day for 2 weeks without modification of the sonogram. We therefore made an initial fetal diagnosis of hypothyroidism using blood sampling, and determined follow-up evaluating ammniotic fluid levels of thyroid stimulating hormone (TSH). The cordocentesis performed at 25 weeks confirmed the presence of fetal hypothyroidism: TSH 20.3 mUI/l (normal value <10), FT4 10.7 pg/ml. Treatment was performed with weekly intra-amniotic injections of thyroxine from 26 to 28 weeks. The fetal goiter decreased and resolution of the polyhydramnios was observed. At 33 weeks the amniocentesis confirmed normal TSH and mature L/S ratio. At the 35th week a premature rupture of membranes occurred and a male infant was born by vaginal delivery (Weight 2590g, Apgar scores 8-10 at 1 and 10 min). The neonatal screening for hypothyroidism was normal and the neonate presented TSH 2.43 mUI/l (range 0.35-4.50), FT3 3.3 pg/ml (range 2.0-4.1), FT4 21 pg/ml (8.0-19.0) and anti-TSH receptor antibodies 9.8 U/L (range <5). All the subsequent tests in the first months of life showed normal levels of thyroid hormones and anti-TSH receptor antibodies. The maternal and fetal outcome is directly related to adequate control of thyrotoxicosis. A careful manegment of PTU dose during pregnancy is needed.