Hi My Sister Is 22 Weeks Preganant And Has Relasped

Hi my sister is 22 weeks preganant and has relasped and smoked meth a couple times, She is currently in a subutex clinic and was doing good she and i both are scared that when the baby is born she will get her son took. She has no intentions what so ever to expose herself to it but i know they have alot of technology out there and was curious if when she has her son is the meth going to show up? I really need help