Postnatal transmission of human immunodeficiency virus type 1: the breast-feeding dilemma.

Human milk has been considered only recently as a source of transmission for the human immunodeficiency virus. The estimated postnatal transmission rate from mothers who acquired human immunodeficiency virus infection while lactating is 26% (95% confidence interval 13% to 39%) and may be in the range of 8% to 18% from mothers who were infected before becoming pregnant. Risk factors for postnatal transmission include maternal immune deficiency and the presence of human immunodeficiency virus-infected cells in milk. Some milk factors may be protective against postnatal transmission such as specific immunoglobulin A and immunoglobulin M and a molecule able to inhibit the binding of human immunodeficiency virus to CD4. In addition to its safety and its birth-spacing properties, breast-feeding provides immunologic protection and an ideal nutritional content to the infant. In a poor hygienic environment artificial feeding dramatically increases morbidity and mortality from diarrheal diseases and respiratory infections. Consequently, according to our current knowledge the World Health Organization and the United Nations Children's Fund reasonably recommend continuing breast-feeding promotion in women living in settings where infectious diseases and malnutrition are the primary causes of infant deaths such as in many developing countries. In settings where infectious diseases and malnutrition are not the primary causes of infant deaths, such as in most of the settings in the developed world, the advisory group recommends against breast-feeding for mothers with proved human immunodeficiency virus-1 infection.