Late onset postpartum psychoses

It has been known since the eighteenth century that postpartum psychoses can begin several weeks after childbirth, not during the first fortnight. There are almost 400 non-organic episodes in the literature, starting more than 3 weeks after the birth; some of them are recurrent. The distinction of this disorder from early onset puerperal psychosis is supported by the distribution of onsets (which shows a steep fall after 14-15 days), survey data and the association with later pregnancies, not the first. Marcé believed that these late onsets were related to the resumption of menstruation. This is a hypothesis worth investigating.