I think it's pretty important to not just focus on the 'mood' of the mom but on the logic. If she was in poverty, in an abusive relationship, if she was young and felt her life was now over, these are logical reasons to be sad and she should not be considered flawed. It is important to not medicate or counsel women out of their 'hangup' of depression when the real culprit is social policy that makes it so hard to be and afford to be a mother. We need universal birth bonus, universal funding per child till age 18, income splitting as a tax option, universal maternity benefits that flow with the child and we need pension benefits for the caregiving years. In that way those women who choose to or end up being pregnant have a lot more win-win options than just being sad. To learn that their low income, low self-esteem, status continues through much of the life of the child and may lead to the child acting up is not a flaw of the mother. It is a flaw of social policy that penalized the entire family, basically for being.
We can fix this. First step is to stop medicalizing and blaming mom.