Who should be asking new mom's about post partum depression?

Here is a great article about how many women with post partum depression are “falling though the cracks”. Did your OB ask you about symptoms of depression or anxiety? Did your child’s pediatrician? Who would you be more comfortable talking to?
http://parenting.blogs.nytimes.com/2013/07/17/who-will-screen-for-postpartum-depression/?