By the third trimester, only about 2% of the women smoke as much as a joint a day, while abstention has gone up. I wondered if these women were all changing to crack cocaine, which was popular about this time, from 1982-1984, around the time that we started getting a lot of cocaine in Pittsburgh. But we do have cocaine data and the answer is no, they weren't. It seems as if their decrease in use was just a natural aging out, something that just decreased as they got older.