I found an excellent article on Health Commentary calling for universal screening for PPD written by Amy Gagliardi, a writer and research based at Yale University. Check out the whole piece, but here is a highlight:

Wilen and Mounts in their article, Women with Depression – “You Can’t Tell by Looking” suggest that when screening for depression in the health care setting is based on clinical observation alone, 50% of women suffering from depression are missed. In a study of 888 pediatricians, Olson et al conclude that even during the postpartum period when pediatricians have frequent contact with mothers and babies, pediatricians rarely identify maternal depression through a routine inquiry about symptoms or through family history. In fact, the most common identification method reported was the physician’s overall impression or the impression in combination with 1 or 2 questions about the mother’s symptoms. Only 4% of the physicians in this study reported using formal diagnostic criteria to identify maternal depression while none reported using a validated screening tool to identify maternal depression.

Universal screening is a necessary prerequisite towards the identification and treatment of maternal depression and this is not a responsibility specific to any one discipline. Whether we are discussing perinatal depression, which is depression during pregnancy and the postpartum period, or depression at any time throughout the life course, systematic and universal screening is the most effective way to identify depression. Of interest is a study which utilized a 2 question screen of mothers during well child visits. One group of mothers received the screen on paper while the other group was screened by means of a scripted interview. Although both methods were proven to require very little time, the paper screen was verified to be a more effective model.