Risk factors for perinatal transmission of human immunodeficiency virus type 1 in women treated with zidovudine. Pediatric AIDS Clinical Trials Group Study 185 Team

N Engl J Med. 1999 Aug 5;341(6):385-93. doi: 10.1056/NEJM199908053410601.

Abstract

Background: Maternal, obstetrical, and infant-related factors associated with the risk of perinatal transmission of human immunodeficiency virus type 1 (HIV-1) were identified before the widespread use of zidovudine therapy in pregnant women. The risk factors for transmission when women and infants receive zidovudine are not well characterized.

Methods: We examined the effects of maternal, obstetrical, and infant-related characteristics and maternal virologic and immunologic variables on the risk of perinatal transmission of HIV-1 among 480 women and their infants, all of whom received zidovudine. The women and infants were participating in a phase 3 trial of passive immunoprophylaxis for the prevention of perinatal transmission.

Results: In univariate analyses, the risk of perinatal transmission was associated with each of the following: decreased maternal CD4+ lymphocyte counts at base line; decreased maternal HIV p24 antibody levels at base line and delivery; increased maternal HIV-1 titer at base line and delivery; increased maternal HIV-1 RNA levels at base line and delivery; and the presence of chorioamnionitis at delivery. In multivariate analyses, the only independent risk factor was the maternal HIV-1 RNA level at base line (odds ratio for transmission, 2.4 per log increase in the number of copies; 95 percent confidence interval, 1.2 to 4.7; P=0.02) and at delivery (odds ratio, 3.4; 95 percent confidence interval, 1.7 to 6.8; P=0.001). There was no perinatal transmission of HIV-1 among the 84 women who had HIV-1 levels below the limit of detection (500 copies per milliliter) at base line or the 107 women who had undetectable levels at delivery.

Conclusions: Among pregnant women and their infants, all treated with zidovudine, the maternal plasma HIV-1 RNA level was the best predictor of the risk of perinatal transmission of HIV-1. Antiretroviral therapy that reduces the HIV-1 RNA level to below 500 copies per milliliter appears to minimize the risk of perinatal transmission as well as improve the health of the women.

Publication types

  • Clinical Trial
  • Clinical Trial, Phase III
  • Multicenter Study
  • Randomized Controlled Trial
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Analysis of Variance
  • Anti-HIV Agents / therapeutic use*
  • CD4 Lymphocyte Count
  • Female
  • HIV Antibodies / blood
  • HIV Core Protein p24 / immunology
  • HIV Infections / drug therapy
  • HIV Infections / transmission*
  • HIV Infections / virology
  • HIV-1 / genetics
  • HIV-1 / immunology
  • HIV-1 / isolation & purification*
  • Humans
  • Infant
  • Infant, Newborn
  • Infectious Disease Transmission, Vertical*
  • Logistic Models
  • Pregnancy
  • Pregnancy Complications, Infectious / drug therapy
  • Pregnancy Complications, Infectious / virology*
  • RNA, Viral / blood*
  • Risk Factors
  • Viral Load
  • Zidovudine / therapeutic use*

Substances

  • Anti-HIV Agents
  • HIV Antibodies
  • HIV Core Protein p24
  • RNA, Viral
  • Zidovudine