Vertical human immunodeficiency virus transmission: a study of placental pathology in relation to maternal risk factors.

We examined 48 placentas of human immunodeficiency virus (HIV)-exposed pregnancies morphologically for HIV-specific changes and immunohistologically for the presence of HIV antigen and RNA. Findings were correlated to infectious states of the children and maternal risk factors. Few HIV antigen-positive Hofbauer cells and HIV RNA positive syncytiotrophoblast and Hofbauer cells were detected. HIV-positive cells in the placenta did not correlate with intrauterine infection and maternal immunologic parameters. Light microscopically, we found two changes: immaturity of the terminal villi and allantois vasculopathy. These changes, however, are not HIV specific. Our results show that vertical HIV transmission cannot be diagnosed by morphological examination of the placenta.