Vertical hepatitis C transmission increased by HIV.(Obstetrics)

Two recently published studies demonstrate that the risk of transmission of hepatitis C from mother to infant is increased by concomitant HIV infection, but unlike HIV, the risk of vertical transmission of hepatitis C is not reduced by elective cesarean section.

Additionally, the larger of the two studies turned up the surprising result that girl babies are at twice the risk of vertical transmission as are boys (J. Infect. Dis. 2005;192:1872-9).

That study, by the European Paediatric Hepatitis C Virus Network, involved 1,479 pregnant women with confirmed hepatitis C infections from 33 sites across Europe. They and their babies were followed prospectively over at least 24 months.

Infants were counted as being infected only if they tested positive (by an RNA polymerase chain reaction test and/or by the presence of anti-hepatitis C antibodies) after the age of 18 months. This is the age by which passively acquired maternal antibodies have almost always disappeared.

The overall hepatitis C vertical transmission rate was 6.2%. Among mothers who were coinfected with HIV, the transmission rate was 8.7%, significantly higher than the 5.5% rate seen among mothers who were infected only with hepatitis C.

After adjusting for maternal HIV infection status, mode of delivery, prematurity, and infant feeding type, the study showed that female infants had 2.07 times the risk of vertical transmission as males, a statistically significant increase.

In this study, a number of factors showed no significant association with vertical transmission.