HIV detection in amniotic fluid samples. Amniocentesis can be performed in HIV pregnant women?

OBJECTIVES: To assess amniotic fluid (AF) HIV contamination as a marker of intrauterine HIV infection and to evaluate amniocentesis as a risk factor for vertical HIV transmission when the mother was under antiretroviral treatment.

STUDY DESIGN: Three hundred and sixty-six HIV pregnant women were included in the study. AF was obtained from three groups of patients: (a) genetic amniocentesis before 1997 (n=11); (b) amniocentesis a few days before the delivery day (n=18); and (c) AF collected on delivery (n=38). An univariate study was conducted to analyze amniocentesis as a risk factor of HIV transmission (groups a and b). Groups b and c were recruited after 1997; these patients were under combined antiretroviral treatment, they were studied to relate AF HIV contamination with fetal infection and maternal blood viral load at delivery (n=56).

RESULTS: From 1984 to 1996, before antiretroviral therapy use in HIV pregnant women, transmission rate was 17%. In the group of patients who underwent genetic amniocentesis (group a) it was 30% (3/10) versus 16.2% (40/247) for patients without amniocentesis. Between 1997 and 2000 transmission rate was 3%. In group b it was 0% (0/18) when amniocentesis was done versus 3.7% (3/81) if no amniocentesis was done (no statistical differences). AF virus was undetectable in all samples (n=56) and no newborn infection was observed after the follow up.

CONCLUSIONS: Amniotic fluid virus load was undetectable when maternal antiretroviral therapy was used, even if the virus was detectable in maternal blood samples. This finding raises the possibility to perform amniocentesis, when it is indicated, to provide the mother with an adequate antiretroviral treatment.