What are the risk factors for mother-to-child transmission? The level of hepatitis B virus in a pregnant woman is directly proportional to the chance of no transmission: high risk: HBV DNA 1.0 x 106 copeis/ml; low risk: HBV DNA 1.0 x 103-6 copeis/ml; very low risk: HBV DNA 1.0 x 106 copeis/ml; integrity of the placental barrier: Factors leading to impairment of placental integrity such as placental abruption may increase the risk of infection. Factors leading to impairment of placental integrity such as placental abruption, invasive paracentesis, preeclampsia, etc. may increase the risk of infection. Fetal genetic susceptibility: Maternal genetic background and immunization status may also be relevant factors influencing the incidence of fetal infection. Relevance of HBeAg: Significance of HBV DNA: Hepatitis B virus DNA (HBV DNA) is the core substance of hepatitis B virus and the basis of viral replication, and it is the most direct, specific, and sensitive detection indicator of hepatitis B infection, and HBV DNA positivity suggests that the hepatitis B virus is replicating and infectious. Continuous replication of hepatitis B virus is the cause of hepatitis B disease, the fundamental purpose of hepatitis B treatment is to inhibit viral replication, positive hepatitis B virus test, indicating that the hepatitis B virus replication is active, while high levels of virus in the blood suggests that the infectiousness of the high, but the high or low level of the virus has no significant correlation with the severity of hepatitis B in pregnant women. It should be noted that viral DNA test is an important reference for hepatologists to make diagnosis and treatment decisions for patients.