I am 25 weeks pregnant, and was smoking marijuana until last week. how long does it take for the drug to get out of the baby's placenta or system?

Very long time: That drug could easily show up in the baby's bowels for the first few days after delivery. You are very unwise to abuse drugs during a pregnancy. Abusing drugs during pregnancy often results in the newborn being taken into protective custody. You should carefully consider your actions.

Fetal brain damage: Previous studies have found that exposure to marijuana during pregnancy can increase a child's risk of having cognitive deficits or psychiatric disorders. While it is not exactly clear how marijuana may affect the fetal brain at a molecular level, it seems the brain may be particularly sensitive to THC (delta-9-tetrahydrocannabinol) during early development, when neurons are forming critical connections. Any drug that interferes with this development could be detrimental to the child, Harkany said.

Thanks for quitting: Quitting is good news and should continue, if you value your baby's health. Otherwise, expect a smaller baby, smaller baby head, potential learning issues,etc. The cannabis is detectable in a new babies poo reflecting exposure as early as 12 wks. If you are not on the radar of CPS, they are unlikely to look. If you resume later, expect a higher risk of crib death and health problems for baby.