What can I do if my pregnant girlfriend has been smoking heroin, marijuana and cigarettes?

She is 6 weeks pregnant and she has been very diligent hiding everything from me. I always knew she was smoking cigarettes occasionally, but she said she quit when she found out she was pregnant. Now, I realize she has been lying all along. She refuses to get treatment and I am very concerned about my unborn child. I realize it sounds ridiculous that I was caught unaware, but I travel a great deal for work and only found out by accident. I don't need lectures, I just need help. I want a healthy baby and a healthy mother. What recourse do I have when it comes to this?