Inclusion Criteria:  Pregnant women >= 18 years of age Gestational age =<34 weeks Test positive for HBsAg Live in study site area in South Dagon and Dagon Seikkan Townships, Yangon Region Give informed consent to participate in the study Newborns and household members of pregnant women enrolled in the study according to previous inclusion criteria  Exclusion Criteria:  Alanine aminotransferase (ALT) levels >300 IU/L  For qualitative study:  Inclusion criteria  Key informants (e.g., healthcare providers and community leaders in the study area) OR HBsAg+ women and their household members in the study area HBsAg- women and their household members in the stud area Give informed consent to participate in the study History of renal dysfunction CrCL < 50mL/min ALT>5 times the upper limit of normal (ULN) Evidence of decompensated cirrhosis (e.g., jaundice, ascites, history of upper gastrointestinal bleeding/esophageal varices, and hepatic encephalopathy) Any concomitant condition or treatment that, in view of the clinical site investigator, would contraindicate participation or satisfactory follow-up in the study HIV positive status unless 1) they are currently on additional ART therapy, or 2) their viral load is demonstrated to be <50 copies. Women who are newly diagnosed with HIV and referred to start a TDF-based regimen may be considered eligible once they have started the TDF-based regimen. Concurrent participation in any other clinical trial without written agreement of the study team Does not intend to deliver within catchment area, and/or intends to migrate before newborn follow-up is complete