INTRODUCTION: Couple-based behavioral interventions (CBIs) have been associated with improved HIV virological outcomes for pregnant women and their male partners living with HIV in observational settings, but have never been tested in a randomized controlled trial (RCT). SETTING: Bwaila District Hospital Antenatal Clinic (Lilongwe, Malawi). METHODS: An RCT was conducted among 500 pregnant women living with HIV (index clients) randomized 1:1 to the standard of care (SOC) or CBI and followed for 1 year. The CBI offered an initial session for index clients, HIV-assisted partner notification, 2 enhanced couple counseling and testing sessions, illustrated materials, and antiretroviral therapy pickup for either couple member at the antenatal clinic. At 12 months, viral load among index clients and male partners with HIV was measured. Risk differences (RD) and 95% confidence intervals (CIs) compared viral suppression (<
1000 copies/mL) between arms. RESULTS: The mean index client age was 26.6 years
most were married or cohabiting (93.3%). Index client viral suppression was 6.5% higher in the CBI arm (88.0%) than in the SOC arm (81.6%). Male partner viral suppression was 16.2% higher in the CBI arm (73.6%) than the SOC arm (57.4%). Overall, couple viral suppression was 7.8% higher (CI: 0.5% to 15.1%, P = 0.04) in the CBI arm (84%) than in the SOC arm (76.0%). Social harms were rare (3.6%) and comparable between arms ( P = 0.8). CONCLUSIONS: This CBI had a positive impact on couple viral suppression. Scaling this CBI to antenatal clients with HIV and their male partners could improve HIV outcomes among expecting families.