This is a difficult question, as there is more to the question than just a simple yes or no answer. Many drugs that are medically prescribed can show up as a positive value on a drug toxin screening, and so more information would be necessary before I could definitively answer in either direction. The most important thing is that your friend's gynecologist will be worried about both the health of her patient and the health of her new baby. If the doctor
ordered a drug test, it is likely because she was worried about something unusual. If she feels that the drug use is potentially a threat to the child--as it almost undoubtedly will be in one form or another--she or he may feel that it is his or her duty to call child protective services or another agency that will be able to help all parties involved.
You, however, can be proactive and make sure that both the baby and the mother are well. At this difficult postpartum time, please provide support and make sure that there are always others available to help both mom and baby. Please speak to your friend and determine if she is getting the medical care that she needs and has the resources she needs to be safe. Please encourage her to speak about this in detail to her doctor.