Need to know how far back they test cord blood for drugs?

Confusing question: If I investigate a newborn that may have been exposed to drugs during pregnancy, there are several sources to explore. Maternal urine during labor, babies urine, babies poo or blood.Rarely, babies hair.Fetal poo begins to form after 12 weeks and may retain usable drug traces for months as will hair. Blood and urine less time. Best never use or avoid suspicion or expect to be caught.