Background Mother-to-infant transmission of hepatitis C virus (HCV) could b
ecome the main route of HCV infection in the future because there are no me
thods available to prevent vertical infection. The aim of this study was to
determine the incidence of mother-to-infant transmission in infants born t
o mothers who tested positive for anti-HCV antibodies and to elucidate asso
ciated risk factors for transmission.
Methods. Screening was conducted for 16 800 pregnant women with an anti-HCV
antibodies test, and 154 mothers were positive. From the positive group 14
1 mothers were enrolled in the study and their 147 infants mere followed fr
om birth for serum alanine aminotransferase activity, anti-HCV antibodies a
nd HCV RNA. HIV infection was tested in 73 of 141 mothers, all of whom were
Results. Thirty-three infants were dropped from the study because they were
followed for <6 months or were not tested adequately. Of the 114 infants f
inally evaluated 9 (7.8%) had detectable HCV RNA. The transmission rate was
not influenced by the mode of delivery [vaginal delivery, 8 of 90 cs. cesa
rean section, 1 of 24 (P = 0.396)] or by the type of feeding [9 of 98 for b
reast-fed infants vs. 0 of 16 for formula-fed infants (P = 0.243)]. All inf
ected infants were born to mothers who had HCV viremia at the delivery (P =
0.040) and to those with a high viral load (P = 0.019).
Conclusions. Our prospective study showed that the transmission rate of mot
her-to-infant HCV infection was 7.8% in anti-HCV antibody-positive mothers.
Risk was related to the presence of maternal HCV viremia at delivery and a
high viral load in the mothers.