Transmission of hepatitis C virus from infected mother to offspring duringsubsequent pregnancies

Background: Several studies have demonstrated that hepatitis C virus (HCV) may be transmitted from mother to offspring. To date, however, little is kn own about the risk of vertical transmission during subsequent pregnancies. The purpose of this study was to evaluate the risk of vertical HCV transmis sion in offspring in subsequent pregnancies of HCV infected women. Methods: In a multicenter study, two groups of index cases were selected. G roup 1 included 75 children investigated for HCV infection during prospecti ve studies of vertical transmission. Group 2 included children born to HCV- infected mothers and found to be HCV infected, independent of studies on ve rtical transmission. All children in the index cases had one or more siblin gs. Anti-HCV, HCV-RNA (determined by polymerase chain reaction), and HCV ge notype were evaluated in all the infected children, their mothers, and sibl ings. Results: The results indicate that a mother who has already delivered an HC V-infected baby is not at greater risk of infecting her second child. Durat ion of maternal infection does not seem to be a risk factor in offspring in fection, because HCV infection is equally distributed among first-born infa nts and infants of subsequent births. Because clustering of HCV infection a mong siblings appeared to be rare in this study, data also indirectly confi rm that the risk of horizontal transmission of HCV among siblings is low. Conclusion: For practical purposes, the current observations indicate that mothers who have already delivered an HCV-infected child can be advised tha t this event does not increase the probability of infecting the second chil d. (C) 2000 Lippincott Williams & Wilkins, Inc.