[Molecular diagnosis of viral materno-fetal infections]

The main viral infections prenatally detected in fetuses are: cytomegalovirus (CMV), parvovirus B19, rubella virus and varicella-zoster virus infections. Prenatal diagnosis is based on the direct detection of the virus by culture (CMV), of its antigens (CMV) or of its genome, essentially by PCR. This direct detection can be done either on fetal blood or on amniotic fluid. Prenatal diagnosis can also be performed by detection of specific IgM in fetal blood (rubella). Non specific markers of viral infections can also help diagnosis. At the present time, prenatal diagnosis is essentially based on the detection of the viral genome in amniotic fluid. In order to better appreciate the severity of fetal infections, some groups have tried to identify prognostic markers of these infections. The viral load could play a role in certain infections (CMV).