IN-UTERO DIAGNOSIS OF CONGENITAL INFECTIONS BY DIRECT FETAL SAMPLING

Counseling for infections during pregnancy has traditionally focused o n the clinical and laboratory findings of infection in the mother and the estimated risk of fetal damage associated with possible transmissi on of infection to the child. Now, with the use of techniques for feta l sampling, it is possible to diagnose infections of the fetus in uter o and to correlate that information with the occurrence of fetal damag e. The techniques that are available for sampling include amniocentesi s, cordocentesis and chorionic villus sampling. The laboratory tests i nclude: a) isolation of the organism in appropriate laboratory systems ; b) detection of the DNA or RNA of the organism directly or with ampl ification with techniques such as PCR; c) detection of the organism by fluorescence or in situ hybridization; and d) identification of IgM o r IgA fetal antibody to the organism by ELISA or similar methods. In u tero infections can be documented for agents such as rubella, cytomega lovirus, parvovirus, Toxoplasma gondii and human immunodeficiency viru s type 1. Further information is needed concerning the sensitivities a nd specificities of these methods for identifying fetal infection and predicting fetal damage.