Fetal thyroid hyperplasia, rhesus isoimmunisation, and amniography

Area of Science:

• Neonatalogy
• Endocrinology
• Pathology

Background:

• Rhesus isoimmunisation can cause haemolytic disease of the newborn.
• Thyroid function in affected infants is not well understood.
• Iodine-containing contrast media are used in prenatal diagnostics.

Purpose of the Study:

• To investigate the incidence of thyroid hyperplasia in infants with haemolytic disease.
• To identify potential goitrogenic factors associated with the condition.
• To explore the relationship between intrauterine transfusions, contrast media, and thyroid abnormalities.

Main Methods:

• Necropsy examination of thyroids from 70 infants with haemolytic disease (1959-1976).
• Comparison with 140 matched control infants without haemolytic disease.
• Analysis of exposure to iodine-containing contrast media, specifically Lipiodol, during amniography.

Main Results:

• Thyroid hyperplasia was found in 16 of 70 infants with haemolytic disease, all of whom received intrauterine transfusions.
• No hyperplasia was observed in control infants or in haemolytic disease cases before 1966.
• Infants with hyperplasia were less mature and smaller than those without, despite similar contrast media exposure.

Conclusions:

• Iodine-containing contrast media used in amniography are identified as goitrogenic factors.
• Infant immaturity may impair adaptive mechanisms, increasing susceptibility to iodine-induced goiter.
• Intrauterine transfusions with contrast media are linked to thyroid hyperplasia in rhesus isoimmunisation.