Twenty-eight HBsAg-positive pregnant women who underwent consultation were recruited from the First Affiliated Hospital of Xi'an Jiaotong University, Shaanxi, China. Twelve of these women willing to receive HBIG administration were assigned to experimental group, while another sixteen without HBIG injection were enrolled as control group. The exclusion criteria for participants were: 1) infection with toxoplasmosis, syphilis, parvovirus B19, rubella, cytomegalovirus, herpes, hepatitis C, HIV, or other viruses; 2) obstetric diseases such as pregnancy-related hypertension, placental abruption, threatened miscarriage, and others.