Depressive illness in the postnatal period is experienced by a significant number of women. It is estimated that somewhere between 20% and 40% of mothers will have sufficient symptoms to be considered depressed in the first year, requiring clinical intervention. This paper will discuss the difficulties of detecting Bipolarity (II) in women presenting with depression in the postnatal period, and put forward a number of non-DSMIV features which may alert the clinician to underlying Bipolarity. This clinical dilemma has been presented by Sharma V, et al Bipolar Disorders 2008 : 10, and Heron J, et al Bipolar Disorders 2009: 11