That would not be relevant to the question of whether Adderall, or the similar methamphetamine, in the generally-used quantities, is harmful to unborn babies. If it is, the additional drug would more likely compound the harm than ameliorate it.
“High” in this sense doesn’t mean feeling good. It means having your heart pound, your head filled with dread, etc. I took a second dose once... VERY bad experience. God KNOWS what it would do to the mind of a developing child.