The three main periods during which a pregnant woman with hepatitis B may transmit the hepatitis B virus to her child are: Prenatal transmission, also known as intrauterine infection, refers to the transmission of the hepatitis B virus to the fetus through the placenta via the mother’s blood before the baby is born. Intrapartum transmission is the most common route of infection. The fetus can be infected by direct contact with maternal blood due to fetal skin and mucous membrane abrasions and placental abruption when passing through the mother’s birth canal during parturition, or by the fetus swallowing amniotic fluid, maternal blood and vaginal secretions containing hepatitis B virus. Postnatal transmission, close contact between mother and infant after delivery leads to infection in infants and children, mainly due to close contact between the mother’s body fluids containing the virus and damage to the infant’s skin and mucous membranes.