Joyce Ann Hafford died without ever holding the son she had tried to save from contracting AIDS by taking an experimental drug regimen administered by government-funded researchers during her pregnancy. But even before her stunned family could grieve, the 33-year-old's death was reverberating among the government's top scientists in Washington. They quickly realized the drugs the HIV-positive woman from Memphis, Tenn., was taking likely caused the liver failure that killed her. Hafford's family members say they were never told NIH had concluded that the experimental drug regimen likely caused her death until the Associated Press gave them copies of NIH's internal case documents this month. They were left to believe Hafford had died from AIDS complications. They tried to make it sound like she was just sick. They never connected it to the drug," said Rubbie King, Hafford's sister. NIH officials acknowledge that experimental drugs, most likely nevirapine, caused her death. The study during which Hafford died recently led researchers to conclude that nevirapine poses risks when taken over time by certain pregnant women. The family says Hafford seemed unaware of the liver risks. They even kept the bottle of nevirapine showing it had no safety warnings.