The objective of this study was to conduct a metasynthesis of evidence of the work of doulas assisting women in labor and during childbirth. Articles between 2000 and 2009 were located in the Medline, PubMed, SciELO, and Lilacs databases using the key search words: doulas, gestation, labor, and alternative therapy. Seven articles were selected for the study and four categories were created: the support provided by doulas; the birth mother's experiences; professional relationship: and opinions and experiences of professionals. The doulas offered physical, emotional, spiritual and social support. Experiments showed that the professionals stimulated the mother/child relationship, oriented towards successful breastfeeding, and contributed to the prevention of post-partum depression. Controversy was observed among professionals regarding acceptance of the role of the doula as a member of the obstetrics team. The doula's care was considered innovative, calming, encouraging, and attended all the needs of the pregnant woman. The conclusion is that qualitative studies on the work of doulas are recent, incipient, but revealing as to the important possibility of humanizing labor and childbirth.