Effect of breastfeeding on mortality among HIV-1 infected women: a randomised trial

Background We have completed a randomised clinical trial of breastfeeding a nd formula feeding to identify the frequency of breastmilk transmission of HIV-1 to infants. However, we also analysed data from this trial to examine the effect of breastfeeding on maternal death rates during 2 years after d elivery. We report our findings from this secondary analysis. Methods Pregnant women attending four Nairobi city council clinics were off ered HIV tests. At about 32 weeks' gestation, 425 HIV-1 seropositive women were randomly allocated to either breastfeed or formula feed their infants. After delivery, mother-infant pairs were followed up monthly during the fi rst year and quarterly during the second year until death, or 2 years after delivery, or end of study. Findings Mortality among mothers was higher in the breastfeeding group than in the formula group (18 vs 6 deaths, log rank test, p=0.009). The cumulat ive probability of maternal death at 24 months after delivery was 10.5% in the breastfeeding group and 3.8% in the formula group (p=0.02). The relativ e risk of death for breastfeeding mothers versus formula feeding mothers wa s 3.2 (95% CI 1.3-8.1, p=0.01). The attributable risk of maternal death due to breastfeeding was 69%. There was an association between maternal death and subsequent infant death, even after infant HIV-1 infection status was c ontrolled for (relative risk 7.9, 95% CI 3.3-18.6, p<0.001). Interpretation Our findings suggest that breastfeeding by HIV-1 infected wo men might result in adverse outcomes for both mother and infant.