Soft drug use after pregnancy compared to use before and during pregnancy.

With the use of information gathered through the course of pregnancy and data collected after delivery, the changing patterns of alcohol, nicotine, and marijuana use of 288 women participating in the Ottawa Prenatal Prospective Study were investigated. The time periods considered were the year before pregnancy, each trimester of pregnancy, and 1, 6, and 12 months post partum. Alcohol use showed the most marked reduction of the three drugs during pregnancy, but a year after delivery prepregnancy drinking patterns (including binging) had been reestablished. An exception to this was a continued reduction of alcohol consumption by those categorized as heavy social drinkers prior to pregnancy. Although not as marked as the alcohol reduction, nicotine use was reduced during pregnancy and continued to remain at the reduced level 1 year post partum. Heavy marijuana use was the least reduced of the drugs during pregnancy and consumption returned to prepregnancy levels a year after the birth of the baby.