Personally I have no experience with PPD (oddly enough) although I do have unipolar depression. It took me years to get an accurate diagnosis because each of my depressive episodes seemed to take on a differing cluster of symptoms. When I asked my psychiatrist why PPD didn't rear it's ugly head, I was told it was because I hadn't deluded myself into believing those marshmellow dreams of motherhood of everything being unicorns and butterflies, that I had an accurate expectation of sleep deprivation, colic, sore breasts and seemingly unending laundry.
When considering this theory, I can definitely see how a new mother who's dealt with infertility might be more at risk for PPD: she's spent so much of her time in focusing on bringing this little one into the world, there's little mental energy left to accurately prepare herself for her world to be turned upside down once this little miracle makes his or her debut.
What kinds of behaviour/symptoms did your W have that has you considering PPD?
Like I said, PPD was never an issue for me but I do have lots of experience with dealing with depression. If you have any questions regarding general depression I can try to answer as best I can if it helps.
M:36 WAH:41 M:16 T:17 D:12 SS:21 Bomb: IDLY 10/29/11 Separated same day, about an hour after the bomb.