Until fairly recently, mentally ill mothers were separated from their new-borns because of the potential danger to the baby. Over the past 50 years, however, we have learned more about the perinatal period, with the development of child psychiatry and interest in maternal postpartum disorders. This knowledge has led psychiatric departments to develop new ways to provide care without separating mentally ill mothers from their babies. Joint full-time admissions began in Great Britain in 1948. The first Mother-Baby Unit (MBU) in France opened in 1979 and in Belgium in 1990. In 2003, there are 17 MBUs in France and 3 in Belgium. From 1995 to 1998, Odile Cazas and Nine Glangeaud, working with a group of child and adult psychiatrists and psychologists, adapted the English Marcé Checklist to the French and Belgian health and child protective systems and added items useful for research.