Intervention Design Elements Are Associated with Frontline Health Workers' Performance to Deliver Infant and Young Child Nutrition Services in Bangladesh and Vietnam.

Training, supervision, and mass media exposure can be implemented at large scale and contribute to improved FLW service delivery by enhancing knowledge and motivation, which in turn positively influence mother's service utilization and IYCF knowledge. Training, supervision, and mass media to enhance service provision should be considered when designing interventions. This trial was registered at clinicaltrials.gov as NCT01678716 (Bangladesh) and NCT01676623 (Vietnam).