ended friendship because of bad choices..

Had anyone just drifted away from a friend? Let go of a friend because of their life choices?
Me and my best friend have defiantly grown apart in the last two years. Now that's she's having another child, I def don't agree with her doing drugs while pregnant.
I know it's not my body and I can't tell her what to do, but even when I mention the slightest thing, she flips out and doesn't speak to me for weeks. It really sucks that I'm Losing my best friend, but I can no longer stand by her side when she is hurting her unborn child with the substances she is putting in her body.
Anyone gone through something similar?