Vasopressin, also known as Anti-Diuretic Hormone, is present in varying amounts in every human body at all times. It regulates the concentration of our urine, and thus regulates blood volume.
So unless this person wants to argue that what's making some new mothers suicidal is insane amounts of water retention and the discomfort that arises from being bloated, I would say that this article is a pantsload.
Reminds me of Mark Twain - "Why do we laugh at births and cry at deaths?...Because we aren't the party involved..."
Postpartum would refer to the mother.