Objective: This study examined the impact of the full 3-arm zidovudine regimen on the perinatal transmission of human immunodeficiency virus type 1 (HIV-1) using population-based data.
Methods: We retrospectively ascertained information on zidovudine prescription and other characteristics of HIV-infected pregnant women and children for birth cohort years 1993, 1995, 1996, and 1997 using HIV/acquired immunodeficiency syndrome registry data from a state health department supplemented by medical record reviews.
Results: The transmission rate decreased from 12.5% in 1993 to 4.6% in 1997. The proportions of HIV-1-infected mothers and children who were prescribed all 3 arms of zidovudine increased from 68% in 1995 to 93% in 1997. Unadjusted and adjusted odds ratios for the relationship between the prescription of 3 arms of zidovudine and the infants' HIV status were 0.19 (95% confidence interval: 0.05-0.84) and 0.15 (95% confidence interval: 0.02-0.96), respectively.
Conclusion: Perinatal HIV-1 transmission rates have decreased over time. This study demonstrates the effectiveness of the rapid implementation of the United States Public Health Service recommendations for the comprehensive use of zidovudine among HIV-1-infected pregnant women in a predominantly rural state.