Vertical transmission of hepatitis C virus in New Zealand

To investigate the transmission of hepatitis C virus from viraemic mothers to infants.

The study group comprised 54 hepatitis C ribonucleic acid (RNA) positive, human immunodeficiency virus (HIV) negative women attending antenatal clinic, their infants when born, 12 previous children and 44 children of 29 additional nonpregnant, viraemic women. During the study period there were 60 live births (1 set of twins, 5 sequential pregnancies). All infants were tested at birth for hepatitis C virus (HCV) RNA. Thirty infants were retested at 6 months or later. Breast milk from 30 mothers was tested for HCV RNA. The 56 other children were tested for antibody to HCV and HCV RNA.

Of the 60 infants tested at birth, 30 failed to attend a 6 month or later followup, 2 infants were HCV viraemic by six months of age, 2 infants had one episode of possible HCV RNA positivity followed by loss of detectable HCV RNA and 26 have shown no evidence of HCV infection. Five of the 30 breast milk samples tested were positive for HCV RNA. Four older children of viraemic mothers were HCV RNA positive.

In this study, 2 of 30 (6.6%) of infants born to HIV negative, HCV viraemic mothers acquired HCV infection. Breast milk remains a possible contributory source of infant HCV infection. Management of babies born to HCV viraemic mothers should include retesting of baby for HCV RNA at 3 to 6 months of age.