What type of drugs would a mother take if the baby was born wityh amphetamines and opiates in it's sysyem?

We are adopting a baby that was born with amphetamines and opiates in it's system. I am not familiar with drugs at all. What kind of drug would the mother be taking to get this mixture to her unborn child. I highly doubt it is prescription, as she would never go to the dr while pregnant.I'm sure it's a street drug one could make at home. I want to do research on this and worst case scenarios we could look for as the baby's central nervous system grows. We love the baby no matter what, but what kind of help could she need? I can only get those answers if I know what drug to look up, I guess. We see a neurologist soon. Just curious, meanwhile. Thanks