xvi, 243 p. : ill. A print copy of this thesis is available through the UO Libraries. Search the library catalog for the location and call number. / Human birth represents a complex interplay between our evolved biology and the cultural norms and expectations surrounding birth. This project considers both the evolutionary and cultural factors that impact the birth outcomes of teen mothers that received support from a trained labor support person, or doula. Doula support has repeatedly been found to decrease the length of labor, the use of pain medication, the rates of caesarian section, and instrumental births and to increase rates of breastfeeding and bonding. However, virtually no studies evaluate why these positive outcomes occur. Current life history models suggest that traits such as short inter-birth intervals, early weaning, extended dependency, and simultaneously raising multiple dependent offspring co-evolved with child-rearing support from multiple caregivers. These models suggest that mothers should be particularly sensitive to perceived cues of social and material support for childrearing; doulas might provide such cues. The goal of this project was to explore how doula support impacted teen mothers' perceptions of their birth experience and outcomes. Data for the project were drawn from three sources: a 15-month participant observation at a non-profit organization providing doula support to teen mothers, 20 semi-structured interviews with mothers who received doula support for the birth of their babies, and by my attendance as a doula at over 50 births. Results suggest that teen mothers experience upheavals in social relationships with their friends, families, and partners following the discovery of their pregnancy. Participants indicated that doula support increased their knowledge of the birth process, provided unbiased and non judgmental support and information, gave them confidence in their ability to give birth, and encouraged mothers to be proactive in communicating with their care providers. Teens used friendship and kinship terms when describing their doula, suggesting that doula support provides cues of kinship that women have used throughout evolutionary history to assess the availability of alloparental care. While doulas themselves provide salient cues of social support, participants also indicated that doulas increased support from fathers and families, thus mobilizing support from existing social networks. Cues of adequate support may lead to increased maternal investment, thereby improving both maternal and fetal outcomes. / Committee in charge: Lawrence Sugiyama, Chairperson, Anthropology Frances White, Member, Anthropology; James Snodgrass, Member, Anthropology; Melissa Cheyney, Member, Not from U of O; John Orbell, Outside Member, Political Science