Post-partum depression is fake, it's the result of ego death from someone whose told they're the center of the universe by every institution/authority suddenly being forced to come second. Some can't cope and go ballistic, usually aided by the psych industry
I'm not saying there will be no adjustment to being a mother. Women will react in their own ways, and it will be stressful. But most women (and men who are now fathers) make the adjustment and are fine. They give in and accept that they aren't number 1 anymore. That they have less freedom and more responsibility, and that it's not always pats on the back and attaboys/girls