MATERNAL PREDICTORS OF PERINATAL HUMAN-IMMUNODEFICIENCY-VIRUS TRANSMISSION

This analysis sought to identify characteristics of pregnant human immunodeficiency virus type 1 (HIV-l)-infected women that predict mother-to-child HIV-1 transmission. Pregnant and immediately postpartum women at risk for HIV were enrolled at obstetric and pediatric care settings in New York City from 1986 to 1992. Demographic and behavioral characteristics, clinical illness, T lymphocyte subsets, immunoglobulin concentration and syphilis serology were collected on the women. Infants were followed to determine HIV infection classification according to Centers for Disease Control and Prevention criteria for HIV-1 in children. Transmission rates were calculated for women who gave birth more than 15 months before the analysis. Of 172 HIV-l-infected women with known outcome 49 (28%) had infected infants. The transmission rate (TR) was significantly higher among women with <280 CD4+ cells/mu l (lowest CD4+ quartile) than with CD4+ counts >280 (48% vs. 22%; P = 0.004; odds ratio, 3.4; 95% confidence interval (1.5, 7.8)); a similar trend was seen by CD4+% quartile. No difference in TR was seen comparing women by CD8+ count quartile but marginally higher TR was seen among women with CD8+% greater than or equal to 51% than with CD8+% <51% (TR = 41% us. 24%; P = 0.076; odds ratio, 2.2; confidence interval (1.0, 5.1)). The highest TR, 62%, was seen in women with both CD8+ count above the median and CD4+ count in the lowest quartile. No significant difference in TR was seen between women with and without HIV-related illness, although the TR was 53% among women hospitalized in the previous year for pneumonia compared with 25% in others (P = 0.03). TR was somewhat lower in women who delivered by cesarean section than vaginally (entire cohort: 18% vs. 32%, P = 0.11; prenatal enrollees only, 17% vs. 38%, P = 0.045). No factor or combination of factors was both highly sensitive and specific for predicting mother-to-child HIV transmission. A possible relationship between transmission and mode of delivery deserves further investigation.