This is something that is a highly controversial topic that I dont think anyone is going to ever agree on. I think there is some question on this forever. There is some proof that it works for some people and some proof it works during pregnancy and especially helps in the case of post-partum depression but you need to leave it in your doctors hands.
Given the controversy surrounding antidepressants and children, and how they affect their young minds, I would apply this same logic to fetuses in the womb. Considering that babies in the womb share blood and nutrients with the mother, it seems that the baby will be unwillingly exposed to significant doses of chemicals. Since we do not know how these chemicals affect children we should show caution and disallow this practice until it is proven to be safe.
There are better ways to get your serotonin and dopamine levels stabilized without relying on mind numbing SSRIs. With all the terrible side effects they have on adults, I can imagine that they'd have even more dangerous side effects with unborn children. Antidepressants are a scam and are meant to keep people who think differently brainwashed.
During pregnancy the unborn child is pretty much held captive to whatever the mother puts into her bloodstream whether it be good nutrients or bad drugs. We know an awful lot about the consequences of speed or alcohol on an unborn child, enough to know that they can cause developmental problems, if not downright dependency. It's not something I know enough about, but if the mother is being treated medically for depression, is the baby also being treated for depression? Is the baby depressed? Anti-depressants have been shown to have adverse mental side affects, so how can we know how it affects the developing mind of an unborn child?