So the laws regarding these things vary by state and jurisdiction. Where I live if a woman presents to the hospital to deliver and has had no prenatal care or very limited prenatal care it triggers the hospital to drug test her. If she tests positive a report is made to CPS. A positive drug test alone is not enough to remove a baby from its mother, however if it turns out through an investigation that there are other risk factors then a warrant will be sought to remove the baby from the mother.

I'm assuming due to the outcome in the op article, there were no other risk factors and they were somehow able to tell her story was legit. It's scary to think that could happen, but infants are the most vulnerable and most at risk when parents are drug addicts. It's just shitty all the way around.