[AS PER AMENDMENT 1/27/99: For maternal dosing, one Combivir tablet bid can be substituted for the individual formulation of 3TC and ZDV. For mothers who receive Combivir during the antepartum period, Combivir is held during labor and delivery, and the separate formulations of ZDV and 3TC are used. Patients who prematurely discontinue study treatment should continue to be followed on study for the duration of the study.]