Inclusion Criteria:  Age > 18 years Weight > 50 kg Documented HIV infection At least 4 weeks of ART and virally suppressed on dolutegravir plus two NRTIs Undetectable HIV-1 viral load Pregnancy at 20-34 weeks as confirmed by ultrasound Singleton pregnancy  Exclusion Criteria:  Confirmed or suspected TB disease Likely to move from the study area during the study period Known exposure to pulmonary TB cases with known or suspected resistance to isoniazid or rifampicin in the source case TB treatment within the past year TB preventive therapy within the last year Sensitivity or intolerance to isoniazid or rifamycins On nevirapine, etravirine, rilpivirine, PI-based, or raltegravir-containing ART regimens Suspected acute hepatitis or known chronic liver disease; HBsAg positivity; severe hepatic impairment Alanine aminotransferase (ALT) ≥ 3 times the upper limit of normal (ULN) Total bilirubin ≥ 2.5 times the ULN Absolute neutrophil count (ANC) < 750 cells/mm3 Creatinine clearance < 50 ml/min Self-reported alcohol use exceeding 21 units per week Karnofsky status < 80 On prohibited medications e.g. dofetilide