AIMS: A placenta with hepatitis B virus (HBV) is one of the main reasons for transplacental transmission during pregnancy. This study aims to explore the factors influencing the presence of hepatitis B surface antigen (HBsAg) in the placenta and the synergistic effect of these factors. METHODS: A total of 155 placentae and blood specimens were collected from HBsAg-positive mothers and their newborns. HBsAg in placenta was detected using the immunohistochemistry method. HBV serum markers were detected using enzyme-linked immunosorbent assay (ELISA) and polymerase chain reaction (PCR) methods. RESULTS: The results showed that hepatitis B e antigen (HBeAg) positive, or HBV DNA positive status, is significantly associated with an HBsAg-positive placenta. A synergistic effect was present. The hazard ratio for a HBsAg-positive placenta in mothers with HBeAg and HBV DNA was 1.97 times higher than the sum of the independent relative risk of each separate effect (synergy index, S=1.97). There was a statistically significant association between HBsAg in newborns and HBsAg in placenta, and the risk of newborns with HBsAg was greater (odds ratio values 3.33 and 5.31, respectively) when placental cells close to the fetal side were HBsAg positive. CONCLUSIONS: Being positive for HBeAg and/or HBV DNA are significant risk factors for HBsAg in the placenta. HBsAg can pass through the placenta via cellular transfer, possibly contributing to transplacental transmission.
AIMS: A placenta with hepatitis B virus (HBV) is one of the main reasons for transplacental transmission during pregnancy. This study aims to explore the factors influencing the presence of hepatitis B surface antigen (HBsAg) in the placenta and the synergistic effect of these factors. METHODS: A total of 155 placentae and blood specimens were collected from HBsAg-positive mothers and their newborns. HBsAg in placenta was detected using the immunohistochemistry method. HBV serum markers were detected using enzyme-linked immunosorbent assay (ELISA) and polymerase chain reaction (PCR) methods. RESULTS: The results showed that hepatitis B e antigen (HBeAg) positive, or HBV DNA positive status, is significantly associated with an HBsAg-positive placenta. A synergistic effect was present. The hazard ratio for a HBsAg-positive placenta in mothers with HBeAg and HBV DNA was 1.97 times higher than the sum of the independent relative risk of each separate effect (synergy index, S=1.97). There was a statistically significant association between HBsAg in newborns and HBsAg in placenta, and the risk of newborns with HBsAg was greater (odds ratio values 3.33 and 5.31, respectively) when placental cells close to the fetal side were HBsAg positive. CONCLUSIONS: Being positive for HBeAg and/or HBV DNA are significant risk factors for HBsAg in the placenta. HBsAg can pass through the placenta via cellular transfer, possibly contributing to transplacental transmission.