Is it bad to take adderall (dextroamphetamine and racemic amphetamine) while pregnant? if so why?

Adderall/Pregnancy: Adderall (dextroamphetamine and racemic amphetamine) is a pregnancy category C drug. This means we don't know whether it will harm an unborn baby. It could cause premature birth, low birth weight, or withdrawal symptoms in a newborn if mom is taking the medicine during pregnancy. Only you and your doctor can decide whether the risk is worth the benefit in you.