Mother-to-Infant Transmission of Hepatitis C Virus
Virological and clinical data from 73 hepatitis C virus (HCV)–infected pregnant women who gave birth to 75 children were merged retrospectively, by logistic regression analysis, to investigate risk factors for vertical transmission of HCV. Eighty-two percent of the HCV-infected mothers were HCV-RNA–positive during pregnancy, and 10% were coinfected with human immunodeficiency virus (HIV). Nine children were HCV infected, 1 was HIV infected, but none was HIV-HCV coinfected. Among vaginal deliveries, the mean HCV load of mothers who transmitted HCV to their infants was higher than that of those who did not (8.1×105 vs. 1.4×104 copies/mL; P=.056). A reduction in umbilical cord–blood pH (relative risk, 3.9; P=.04) or the occurrence of perineal or vaginal laceration (relative risk, 6.4; P=.028) during vaginal delivery significantly increased the risk of vertical HCV transmission. In conclusion, high maternal viremia, infantile hypoxia, and intrapartum exposure to virus-contaminated maternal blood increased the risk of HCV transmission during vaginal deliveries. Consequently, cesarean section may reduce the risk of vertical HCV transmission in selected cases
In developed countries, the majority of new hepatitis C virus (HCV) infections are acquired through injection drug use (IDU). Although vertical transmission of HCV from mother to child during delivery is a rare route of infection, with reported average transmission rates of 5%–10%, it is the predominant mode of infection among children
Until now, only a few risk factors influencing vertical HCV transmission during the perinatal period have been identified (i.e., human immunodeficiency virus [HIV] type 1 coinfection and the presence of HCV RNA in maternal blood). However, it is still controversial whether high maternal virus load also poses a higher risk for transmission. Furthermore, the timing of perinatal transmission is uncertain, and understanding of the obstetrical factors that influence vertical transmission of HCV is still limited. Although several studies did not find an increased risk of transmission during vaginal delivery, a recent investigation of a large cohort found evidence that elective cesarean delivery results in a reduction in mother-to-child transmission rates. Because the factors influencing transmission are still unclear, screening of pregnant women for HCV infection is currently not recommended, and preventive measures during delivery are not available. This uncertainty about risk factors that influence vertical transmission of HCV stands in contrast to mother-to-infant transmission of HIV-1, where risk factors for transmission have been clearly identified (i.e., plasma HIV-1 RNA level and vaginal delivery). As a consequence, medical interventions that significantly reduced vertical transmission rates of HIV-1, including antiviral drugs and elective cesarean section, have been introduced