Just a quick question.

It depends on what drug and how often it is done.

HOWEVER, any illicit drug that is taken can be detected in the meconium if tested.

It can depend on the drug, amount taken, and gestation of pregnancy which will determine baby's stage of development. Some things could be potentially very damaging at various stages of development, but not as much of a concern (although obviously not a good idea) at other times in the pregnancy.

Say it was done four days ago, cocaine

Cocaine will eventually get out of baby's system if not taken again.

However, if it is continuously taken (my facility tests meconium for drug use) the mother risks having a potentially life threatening condition called a placenta abruption. This can kill both mother and baby.

Also, baby will suffer withdrawals from the drug if taken on a regular basis.