Although administration of ZDV to mother-infant pairs has dramatically reduced perinatal HIV infection, the goal is to reduce it further to less than 2%. In order to achieve this, combination strategies need to be developed for 2 purposes: 1) to reduce the perinatal transmission rate to goal levels; and 2) to provide other combination therapies for HIV-infected mothers whose virus has become resistant to ZDV, who have a very high viral load, or who have previously transmitted HIV while on ZDV. This study adds 3TC (another reverse transcriptase inhibitor) and SQV (a protease inhibitor [PI]) [AS PER AMENDMENT 08/15/00: with low-dose RTV (another PI)] to the mother's ZDV regimen.