**Background:** Between 2011 and 2019, BBC Media Action implemented the Shaping Demand and Practices (SDP) project in Bihar, India, to address high maternal and child mortality by improving reproductive, maternal, neonatal, and child health (RMNCH). The program was part of the broader Ananya initiative, funded by the Bill & Melinda Gates Foundation, and aimed to tackle both supply-side and demand-side barriers. A key focus was improving the quality of engagement between frontline health workers (FLHWs) and families, recognizing that FLHWs are the last mile of the health system. The project developed four mobile health (mHealth) services: Mobile Academy (IVR-based training for FLHWs), Mobile Kunji (audio-visual job aid for FLHWs), Kilkari (direct-to-consumer maternal messaging), and GupShup Potli (community audio capsules for group discussion). These services were designed using human-centered, gender-intentional design and were intended to be layered with mass media and community events to create a 'surround sound' effect.
**Methods:** The SDP theory of change was informed by social, behavioral, and communication theories, focusing on determinants such as knowledge, attitudes, self-efficacy, discussion, social norms, and health service access. The project targeted 11 priority RMNCH behaviors across a 1000-day window from conception to age two. Formative research revealed that over half of women in Bihar were illiterate with limited mass media access, but high household phone ownership and a large FLHW workforce presented opportunities. The mHealth services were developed through a five-stage user-centered design process. Evaluations included: an independent RCT for Kilkari in Madhya Pradesh (2018–2020); independent analyses of Mobile Kunji and Mobile Academy in Bihar (2013–2017); and a cross-sectional evaluation of GupShup Potli in Bihar. Qualitative research and secondary analyses of call record data were also conducted.
**Key Results:** Mobile Academy: Over four in five FLHWs (81%) who started the training completed it, and only 1% failed (scored <50% on quizzes). Qualitative assessments found it bolstered RMNCH knowledge and improved communication skills. Kilkari (RCT): Significant effects were found on modern contraceptive use (driven largely by condom use) and child immunization at 10 weeks. Effects on family planning were substantially larger for those exposed to half or more of relevant calls. Greater effects were observed for more marginalized groups (poorer subscribers, disadvantaged castes, less educated families). However, Kilkari did not impact other behaviors like infant and young child feeding, nor did it change reported discussion or information-seeking. Mobile Kunji: Exposure was associated with longer FLHW-family interactions, increased discussion of health information within families, greater trust in FLHWs, and improved knowledge and practices across multiple behaviors under normative influence, including birth preparedness, iron folic acid consumption, exclusive breastfeeding, timely complementary feeding, and dietary diversity. GupShup Potli: Exposure was associated with improved health knowledge, greater interpersonal discussion, and higher reported rates of iron/folic acid consumption and current contraceptive use, though the evaluation had a weak cross-sectional design with multiple biases.
**Clinical Implications:** The findings demonstrate that facilitated communication tools (Mobile Kunji, GupShup Potli) are more effective than direct-to-consumer digital services (Kilkari) at influencing deeply entrenched, norm-driven behaviors like infant feeding. This highlights the critical role of trained, well-equipped FLHWs in driving behavior change, especially for behaviors with limited health system engagement. Direct-to-consumer digital services can complement face-to-face interactions and improve equity by reaching marginalized groups, but their impact is limited to specific behaviors. The layered 'surround sound' approach—combining mass media, community events, and multiple digital tools—is likely necessary to shift social norms and sustain behavior change. Gender-intentional design and equity analysis are essential to ensure marginalized women without phone access are not left behind. The successful government scale-up of Kilkari (24.6 million subscribers across 17 states) and Mobile Academy (235,000+ FLHWs across 16 states) demonstrates the feasibility of integrating digital health solutions into public health systems at scale.