In Greek and other European populations, about 65% of women are healthy carriers of the cytomegalovirus (CMV). As a consequence, CMV appears to be a serious common threat for pregnancies. The risk of fetal CMV infection may be either 25-50% in case of a primary mater­nal infection during pregnancy, or 0.5-3.5% in case of a recurrent maternal infection. The symptoms of congenital CMV infection vary considerably from case to case, and may include severe congenital cytomegalic inclusion dis­ease with signs of prematurity, jaundice with hepato­splenomegaly, thrombocytopenic purpura, and central nervous system damage. We present here an illustrative case of a pregnant woman who was advised by her obste­trician to undergo prenatal molecular testing for CMV, although she was just a carrier of the virus, and she had had no recurrence of infection. The woman and her hus­band came to our Center for genetic counseling, after poly­merase chain reaction (PCR) testing of amniotic fluid indicated the presence of CMV DNA; the obstetrician advised termination of the pregnancy. In order to dis­tinguish between the possibilities of real fetal CMV infec­tion, or of a false positive result due to contamination of the amniotic fluid sample by maternal leucocytes during amniocentesis, we advised an additional immunological and molecular test of the woman’s blood sample.

Enzyme-linked immunosorbent assay (ELISA) testing for serum anti-CMV antibodies was positive for IgG and negative for IgM. The molecular test detected DNA of CMV in total blood of the pregnant woman, but not in her serum. These results indicated that there was no recurrence of CMV infection, and the amniotic fluid sample was simply contaminated by maternal blood. Therefore, the parents were advised to continue the pregnancy with ultra­sound monitoring by the caring obstetrician, and a healthy baby was born. We consider that our contribution in avoid­ing an iatrogenic error was very positive, especially in light of the fact that the first child of the same couple had been previously diagnosed in our Centre as having fronto­nasal dysplasia. This syndrome, characterized by midface defects including cleft lip and palate, was caused by an environmental factor (estrogens prescribed during second month of pregnancy). We discuss here the proper strategy for prevention of a fetal CMV infection, including prenatal molecular testing when it is justified.

Key words: cytomegalovirus (CMV), infection during pregnancy, prenatal testing, genetic counseling, fronto­nasal dysplasia.