Discordant outcome of perinatal transmission of hepatitis C in twin pregnancies.

Background: Mother to infant transmission of hepatitis C virus (HCV) is dependent on significant HCV viraemia being present in the mother. As yet there are no appropriate interventions to prevent perinatal transmission. The investigation of twin pregnancies where only one twin is infected may reveal further information relating to transmission and specific risks. Evaluation of these risks could affect decisions about the management of the deliveries of these mothers while more appropriate interventions are evaluated.

Study Design: The laboratory database was searched for all twins referred for testing at the Children's Hospital Liver Unit. The mothers and health care providers were contacted to gain more information about the pregnancies and deliveries of all of the twins.

Results: Four sets of twins had been investigated for HCV. In all cases only one twin had been infected. In three out of four cases the second twin had become infected. All of the twins were girls and the larger twin in each pair became infected. Premature rupture of membranes was associated with transmission in the only case in which the first-born became infected. There was no invasive foetal monitoring or episiotomy in any of the deliveries

Summary And Conclusions: Transmission of HCV is more likely to affect the second twin, perhaps because placental separation during the delivery of the second twin exposes the infant to infection. Until effective interventions such as vaccination of newborns or antiviral treatment of mothers are evaluated, elective caesarean section could be recommended for HCV twin pregnancies in order to avoid premature membrane rupture and infection of the second twin.