SummaryBackground: In the first half of the twentieth century, women with postpartum psychotic disorders were routinely separated from their babies, whether they were cared for at home or in asylums. Treatment of mothers with their infants started in the 1950s but the reasons for this change in policy have not been explored. Methods: Examination of secondary and primary historical sources, including a systematic manual search of articles in the Journal of Mental Science (19001960) using key-words, use of other journals and successive editions of British textbooks and a search of the Wellcome Institute history of medicine catalogue. Results: The sources used document the influence of the rise of psychoanalysis, the absence of women carers in positions of power in the asylums, changes in psychiatry as a specialty and changes in family structures on the treatment of women with postpartum psychotic disorders. Conclusions: Changes in practice were associated with improvement in psychiatric treatment, changes in the nature of asylums as a result of government policy, changes in family structures with a lack of surrogate care, the development of social psychiatry and the increase in women psychiatrists. Practices in psychiatry are influenced by current paradigms and social and political influences in addition to evidence based knowledge.