Background: Hepatitis C virus (HCV) infection in children is mainly acquired via maternal transmission. Our aim was to identify mother-to-child-transmission (MTC) risk factors, namely those associated with maternal virological characteristics and mode of delivery.
Methods: Women were included between October 1998 and September 2002 in six hospitals in Southern France on the basis of positive HCV serological status. Recorded data included maternal characteristics, circumstances of delivery and laboratory data concerning mother and child. Paediatric follow-up lasted 1 year, and 2 years for children with circulating HCV RNA.
Results: A total of 214 mother-and-child pairs were analysed; 55 (26%) were HCV/HIV co-infected. The probability of HCV transmission was three-fold higher for HCV/HIV-co-infected women (P = 0.05). Twelve children were HCV RNA positive at 1 year of age (MTC = 5.6%); three became HCV RNA negative between 12 (M12) and 18 months of age (M18) and recovered normal alanine aminotransferase levels. Circulating HCV RNA was found in 137 (69%) mothers. Mothers of infected children all displayed HCV viraemia (MTC = 8.8%): six children were born of HCV/HIV-co-infected HCV RNA positive women (MTC = 13.6%) and six from HCV monoinfected women with positive HCV RNA (MTC = 6.5%). When maternal HCV RNA levels were below 6 log-IU/ml, the rate of transmission was significantly higher in the case of HCV/HIV co-infection (odds ratio = 8.3, 95% confidence interval, 1.4-47.5) P = 0.01. This association did not, however, exist for HCV RNA-positive mothers with levels of at least 6 log-IU/ml. Rate of transmission did not differ significantly between children born by vaginal delivery or caesarean section after membrane rupture and those born by elective caesarean section independently of HIV status.