What is the primary risk factor for perinatal transmission of Hepatitis C?

The primary risk factor for perinatal transmission of Hepatitis C is intravenous drug (IVD) use. Hepatitis C is mainly transmitted through blood-to-blood contact, and individuals who use intravenous drugs often share needles or other paraphernalia, which significantly increases the risk of transmitting the virus to others, including potential transmission during pregnancy.

When a woman who has Hepatitis C becomes pregnant, the risk of transmitting the virus to the fetus is notably higher if she has a history of IVD drug use. This is because the likelihood of active viral replication and higher viral loads, which enhance transmission probability, is more common among these individuals.

Other factors, while they can contribute to risk of Hepatitis C transmission, do not primarily relate to perinatal transmission. For instance, while oral sex can carry some risk of transmission, it is drastically lower compared to routes involving blood. Similarly, having multiple sexual partners may increase the risk of acquiring Hepatitis C in general but is not specifically linked to perinatal transmission as directly as drug use. Maternal age over 35 may be associated with some pregnancy risks but is not a recognized risk factor for the transmission of Hepatitis C to the newborn.

Thus, intravenous drug use is the