Background/aims: The aim of this study was to explore the role of breast-feeding in transmission of hepatitis C virus (HCV) to infants of HCV-infected mothers.
Methods: Sixty-five parturient asymptomatic carrier mothers with anti-HCV antibody (index patients) and 42 healthy parturient anti-HCV negative mothers (control subjects) were studied from September 1994 to June 1996. Maternal blood and colostrum were taken from each subject within 5 days post-partum and tested for anti-HCV and HCV RNA. Blood samples were collected from all infants at birth (cord blood) and at 1, 3, 6, 9 and 12 months of age. All infants were breast-fed. By 3 months post-partum, five of 65 index patients developed symptomatic liver disease and three of their infants developed acute viral hepatitis. Genotyping and subsequent nucleotide sequencing of the hepatitis C genome was done on these three symptomatic mother-baby pairs.
Results: Within 5 days post-partum, the 65 carrier mothers had anti-HCV ranging from 1:40 to 1:30,000 and HCV-RNA ranging from 10(2) to 2.5x10(6) copies/ml. Both anti-HCV antibody and HCV-RNA were present in colostral samples but in significantly lower levels (p<0.0001). The five symptomatic mothers had anti-HCV titers ranging from 1:45,000 to 1:90,000 and HCV-RNA ranging from 2.5x10(8) to 4.5x10(9) copies/ml; three of their infants were symptomatic by 3 months of age. Hepatitis C virus genotype (3a) was concordant within each of the three mother-baby pairs, and all three pairs demonstrated greater than 97% homologies between pairs. These three infants were delivered by elective cesarean section at term, breast-fed regularly and there was no apparent maternal breast nipple trauma. None of the remaining infants had evidence of HCV infection up to 1 year of age. All 42 mother-infant pairs from the control group remained anti-HCV negative throughout this study.
Conclusion: Among asymptomatic mothers breast-feeding seems safe. Symptomatic women, especially with high viral loads, should not breast-feed to avoid the risk of viral transmission through breast-feeding.