chances are they will notify social services if the baby is born with pot in its system (they are obligated because pot is illegal) which generally entails follow up (home visits, interview, etc) but they generally don't get involved with mothers who smoke pot. cocaine, speed and other more harmful drugs, absolutely they will take your baby, but have never heard of them taking your baby only because of pot. That being said, you should know that if you continue to have children and any of them are positive for any drugs, they will look more closely if any of your previous babies have popped positive for just marijuana. all in all they are not as concerned with marijuana but still have a legal right to get involved. might be wise to err on the side of caution and make sure you're clean for delivery so the baby is not positive at birth. Also, takes longer for pot to get out of the baby's system than yours. (not really sure how that works, but new babies have been known to test positive whereas their mothers are clean)