Risk factors for perinatal transmission of hepatitis C virus (HCV) and the natural history of HCV infection acquired in infancy

Background. The goal of the present study was to assess risk factors for perinatal hepatitis C virus (HCV) transmission and the natural history of infection among HCV-infected infants. Methods. In a cohort study, 244 infants born to HCV-positive mothers were followed from birth until age >= 12 months. Maternal serum was collected at enrollment and delivery; infant serum was collected at birth and at 8 well-child visits. Testing included detection of antibody to HCV, detection of HCV RNA (qualitative and quantitative), and genotyping. HCV-infected infants were followed annually until age 5 years. Results. Overall, 9 of 190 (4.7% [95% confidence interval {CI}, 2.3%-9.1%]) infants born to mothers who were HCV RNA positive at delivery became infected, compared with 0 of 54 infants born to HCV RNA-negative mothers (). Among HCV RNA-positive mothers, the rate of transmission was 3.8% (95% CI, 1.7%-8.1%) Pp. 10 from the 182 who were human immunodeficiency virus (HIV) negative, compared with 25.0% (95% CI, 4.5%-64.4%) from the 8 who were HIV positive (P < .05). Three infected infants resolved their infection (i.e., became HCV RNA negative). In multivariate analysis restricted to HCV RNA-positive mothers, membrane rupture >= 6 h (odds ratio [OR], 9.3 [95% CI, 1.5-179.7]) and internal fetal monitoring (OR, 6.7 [95% CI, 1.1-35.9]) were associated with transmission of HCV to infants. Conclusion. If duration of membrane rupture and internal fetal monitoring are confirmed to be associated with transmission, interventions may be possible to decrease the risk of transmission.