Teratogen exposure: lack of morphological abnormalities by detailed fetal sonography

Teratogen exposures cause 1-2% of congenital abnormalities. Our anecdotal experience was that detailed fetal sonograms conducted for the indication of teratogen exposure failed to demonstrate significant morphological abnormalities. We reviewed our experience to see how often such examinations yielded positive results. Records from 11 September 1989 to 13 September 1993 were reviewed. All women referred for detailed fetal sonography for the sole indication of exposure to drugs, toxins, or infectious agents and with a sonographic age of 16-24 menstrual weeks were included. All exposures were included in the study, even those without known teratogenic potential. Patients previously diagnosed with a morphological abnormality or with an abnormal level of maternal serum alpha-fetoprotein were excluded.A total of 125 women with 126 singleton pregnancies comprised the study population. Ten women had multiple exposures. Including the multiple exposures, there was a total of 138 exposures, 104 to drugs and other toxins (45 of which were not known human teratogens), and 34 to infections. The only significant morphological abnormality found was a duplicated kidney in a woman with parvovirus exposure. While parvovirus is a cause of anemia and hydrops, it is not a known human teratogen. We therefore assume that this was a coincidental association. We conclude that teratogen exposure is a low-yield indication for detailed fetal sonography.