We developed and piloted a video-based intervention targeting HIV-positive pregnant women to optimize antiretroviral therapy (ART) retention and adherence by providing a VITAL Start (Video-intervention to Inspire Treatment Adherence for Life) before ART. VITAL Start (VS) was grounded in behavior-determinant models and developed through an iterative multi-stakeholder process. Of 306 pregnant women eligible for ART, 160 were randomized to standard of care (SOC), 146 to VS and followed for one-month. Of those assigned to VS, 100% completed video-viewing; 96.5% reported they would recommend VS. Of 11 health workers interviewed, 82% preferred VS over SOC; 91% found VS more time-efficient. Compared to SOC, VS group had greater change in HIV/ART knowledge (p < 0.01), trend towards being more likely to start ART (p = 0.07), and better self-reported adherence (p = 0.02). There were no significant group differences in 1-month retention and pharmacy pill count. VITAL Start was highly acceptable, feasible, with promising benefits to ART adherence.