Childbirth and the immediate postpartum period represent a major transition in a woman's life. This period is considered a vulnerable time for the mother and child in most societies, and rituals for this transition are common. In this study, we present some examples of postpartum customs in a cross-cultural and historical perspective. Also, we present the current knowledge on the possible impact of postnatal care on mental health. Systematic literature searches were performed in Medline, PsycINFO, and the Science Citation Index Expanded (ISI) for the time period 1966 through May 2010. Reference lists in books on pregnancy and childbirth from the University Library in Oslo were used to obtain additional information. We found that the postnatal period seems to be universally defined as 40 days. Most cultures have special postnatal customs, including special diet, isolation, rest, and assistance for the mother. The uniformity of customs across different cultures is striking. However, many postnatal customs that were common before 1950 are no longer existent. The focus on rest and assistance for the mother after delivery has gradually decreased. Studies of associations of postnatal care and mental health in the mother are limited and show inconsistent results. More knowledge is needed on postnatal care and mental health.