Learning Objectives: Identify changes in nicotine metabolism during pregnancy
Abstract:
Problem/Objective: Hair analysis provides an innovative approach for measuring long-term changes in drug metabolism. Recent study has shown increased nicotine metabolism in pregnant smokers. However, nicotine metabolism has not been fully investigated throughout pregnancy. This study uses the disposition of nicotine and cotinine in maternal hair to charaterize nicotine metabolism during pregnancy.
Methods: At the time of delivery, a hair sample and smoking history were collected from three hundred pregnant women in Montreal. The hair samples are sectioned to represent the three trimesters of pregnancy; hair grows approximately 1 cm/month. The amount of nicotine and its major metabolite cotinine are measured by radioimmunoassay. The ratio of nicotine to cotinine is used to reflect nicotine metabolism.
Results: Preliminary results from 7 smokers and 44 nonsmokers are as follows. The nicotine to cotinine ratio in smokers tends to decrease in late pregnancy (Nicotine/Cotinine Ratio: 1st Trimester – 20.3, 2nd Trimester – 15.0 and 3rd Trimester – 15.0). This ratio remains constant in non-smoking women. Nicotine levels in pregnant smokers decreased from 16 ng/mg of hair in the first trimester to 9 ng/mg in the third trimester, without any reduction in smoking (P=0.1).
Conclusions: These results support an increase in nicotine metabolism during late pregnancy. Accelerated nicotine metabolism may explain the limited success of nicotine replacement therapy among pregnant women. The amount of nicotine is likely insufficient to aid smoking cessation during pregnancy; dosages may need to be adjusted. Further investigation is required to determine whether metabolism significantly influences nicotine dependence or addiction.
Back to Poster Session
Back to Cessation, Nicotine, and the Science of Addiction
Back to The 2003 National Conference on Tobacco or Health (December 10-12, 2003)