BACKGROUND: The success of Pediatric AIDS Clinical Trials Group (PACTG) Protocol 076 in preventing vertical HIV transmission prompted intensive efforts to inform lay-persons and professionals about the trial's results. OBJECTIVE: To explore community responsiveness to these efforts by assessing temporal, maternal, and health care factors associated with prescribed antiretroviral therapy before and after PACTG Protocol 076. DESIGN: Retrospective cohort study. SETTING: New York State Medicaid program. PATIENTS: 2607 HIV-infected women who delivered a living child between January 1993 and September 1996. MEASUREMENTS: Adjusted odds of being prescribed antiretroviral treatment in the second or third trimester for women who delivered in period 1 (during the trial [January 1993 to February 1994]), period 2 (after the trial's end and announcement of the results to publication of the results [March 1994 to November 1994]), and period 3 (after publication of the trial results [December 1994 to September 1996]). RESULTS: The adjusted odds of being prescribed antiretroviral therapy increased 21% per month in period 2 and decreased to 3% per month in period 3. In all time periods, the adjusted odds of being prescribed antiretroviral therapy were at least 60% greater (P < 0.05) for women who were treated at an institution that performed HIV clinical trials, received HIV-focused ambulatory care, or had adequate prenatal care visits. After the trial, women receiving methadone treatment had at least twofold (95% CI, 1.5- to 4.3-fold) greater adjusted odds of being prescribed antiretroviral therapy than women who did not take any illicit drugs. Latin-American women, older women, and women born in the United States had greater adjusted odds (P < 0.05) of being prescribed treatment in period 3. CONCLUSION: Community practice responded rapidly to efforts to disseminate the results of PACTG Protocol 076; however, the absolute increase in prescribed therapy was greatest for women who had adequate prenatal visits or were receiving HIV-focused care, care at a site that performed clinical trials, or methadone therapy.