When Does Meconium Form?

Meconium begins to form between the 12th and 16th week of gestation. Meconium drug testing can detect maternal drug use during the last 4 to 5 months of pregnancy. A negative result does not exclude the possibility that a mother used drugs during pregnancy.

How far back does a urine drug test go on a newborn?

These tests detect recent use of cocaine and its metabolites, amphetamines, marijuana, barbiturates, and opiates. Cocaine can be detected in urine 6-8 hours after use in the mother and as long as 48-72 hours after use in the newborn.

When is meconium normally passed?

Normally, the initial passage of meconium occurs within the first 12 hours after birth. Meconium passage will occur in 99% of term infants and 95% of premature infants within 48 hours of birth.