Smoking habits in early pregnancy related to age of smoking debut.

During 1 year, 187 general practitioners in western Norway recruited 530 daily smoking, pregnant women for a smoking cessation study. At the first medical check-up in pregnancy each woman filled in a questionnaire. Women who had started smoking within 15 years of age reported more heavy smoking the last 3 months before pregnancy (P < 0.0001) and at the first check-up in pregnancy (P < 0.01) than those who had started smoking later. They also reported less reduction in smoking habits during earlier pregnancies (P < 0.0001) and more serious tobacco addiction judged by starting smoking early in the morning (P < 0.005). However, even those who had started smoking before 15 years of age reported a reduction of 30% in cigarette consumption during the first few weeks of the present pregnancy. In addition to increasing the antismoking efforts among pregnant women, health education among girls 12-15 years of age to prevent smoking initiation should be intensified.