Re-evaluation of the true rate of hepatitis C virus mother-to-child transmission and its novel risk factors based on our two prospective studies

Objective: To re-evaluate the true hepatitis C virus (HCV) mother-to-child transmission (MTCT) rate and its novel risk factors. Study Design: A comparative study based on our own two prospective studies done during the two periods, 'early' (1989-1994) and 'recent' (1995-2004). Results: All carrier infants became HCV RNA-positive within 3 months after birth. The MTCT and de-carrier rates were, respectively, higher (14.2%) and lower (16.7%) in the recent period, although liver dysfunction of carrier infants was found very frequently (66.7%) in both groups. MTCT occurred significantly when the maternal viral load, serum alanine aminotransferase (sALT) levels and blood loss at delivery were, respectively, more than 10(5) copies/mL, 110 IU/L, and 500 g. No MTCT was found when elective cesarean section was done. Conclusions: The true HCV MTCT and de-carrier rates were found to be much higher and lower than those reported previously. The maternal liver dysfunction (sALT >= 110 IU/mL) and blood loss ( >= 500 g) at delivery are the next risk factors to maternal viral load ( >= 10(5) copies/mL) for MTCT.