Prosecutors argued that the miscarriage Poolaw suffered was from her use of methamphetamine. An autopsy of the fetus showed it had tested positive for methamphetamine, the Associated Press reported, but there was no evidence her use of the substance is what caused the miscarriage. The autopsy showed the miscarriage could have been caused by a congenital abnormality and placental abruption, when the placenta detaches from the womb, the AP said.