This article describes the development of an innovative community-based program, One Hundred Intentional Acts of Kindness toward a Pregnant Woman (100 Acts), which seeks to increase reproductive social capital for pregnant women in south and central Los Angeles communities. Reproductive social capital includes features such as networks, norms, and social trust that facilitate optimal reproductive health within a community. 100 Acts was designed and developed by the Healthy African American Families project, using community participatory methods, to increase local community and social network support for pregnant women. Dialog groups with pregnant women identified specific actions that families, friends, and strangers might do to support pregnancies. Participants primarily wanted emotional and instrumental support from family and friends. From strangers, they wanted respect for personal space and common courtesy. Based on these results, the 100 Acts was created for use in the Los Angeles community. 100 Acts encourages and engages active participation from community members in promoting healthy pregnancies. By seeking to increase community-level reproductive social capital, 100 Acts shifts the provision of social support during pregnancy from a high-risk approach to a population approach. 100 Acts also establishes new social norms about how pregnant women are valued, treated and respected.