You can call based on concern for the child's well being. They might investigate, but they might not. It will create a paper trail though...which is a start. If shes using, its the law for the dr to contact social services too at the time of birth. Honestly, theres not a lot you can do because its very difficult to take a child away from its mother. But you can try....you might save a life. Who knows. Good luck
You could call child protect services and let them know what's going on. They might be able to step in. But if she's still using them when the baby is here they'll probably find it in both of their blood systems and the hospital will most likely get them involved as well. But I hope she realizes she needs to quit before it's too late.
I live in Canada and you can for sure call child services Here it might not do anything because they need to see her doing drugs or under the influence which I don't think is right but it wouldn't hurt to call
Seems like they should be able to like put her in rehab or something. But it's child endangerment even if it hasn't been born yet. I say call, she shouldn't be risking her child's health like that