Drinking and smoking at 3 months postpartum by lactation history.

A spontaneous decrease in maternal drinking and smoking often occurs during pregnancy. The present study was conducted to determine if these lower levels of maternal drinking and smoking during pregnancy persist into the postpartum period, and if so, to determine if they are related to breastfeeding. Drinking and smoking were estimated in three cohorts of postpartum women who had been followed since pregnancy. The first group never breastfed their infants; the second group breastfed for less than 1 month; the third group breastfed for more than three months. (Women who weaned between one and three months were not studied). Drinking and smoking in all three groups decreased sharply during pregnancy but rose again in the 3 months after delivery, though not to levels that were reported before conception. Usual drinking in the third month postpartum did not differ significantly among the three lactation groups. However, women who were still nursing were less likely to report occasional episodes of heavy drinking (binges) in this month than women who had weaned early or never breastfed. Women nursing in the third month postpartum were also significantly less likely to smoke during the month; if smoking, they were less likely to smoke heavily. These differences in postpartum drinking and smoking were not due entirely to habits before conception or to the influence of other potentially confounding variables.