Adverse effect of amniofetography on fetal thyroid function.

Amniofetography is a valuable tool for the diagnosis of fetal malformations. This technique is being used routinely in pregnancies carrying a high risk of external fetal malformations. There are very few published data concerning the effect of radiopaque dyes, containing large amounts of iodide, on fetal thyroid function. We have performed serial determinations of serum thyrotropin and thyroxine in seven newborn infants to assess the effect of amniofetogrpahy on fetal thyroid function. This work demonstrates that amniofetography induces a transient impairment of fetal thyroid function.