Smoking during consecutive pregnancies among primiparous women in the population-based Norwegian Mother and Child Cohort Study.

Introduction: This study investigated changes in smoking behavior across pregnancies in a sample of 10,890 primiparous women participating in the prospective population-based Norwegian Mother and Child Cohort Study (MoBa) in order to identify risk factors that may inhibit smoking cessation and promote smoking during a woman's second pregnancy.

Methods: Registry information regarding smoking, age, marital status, parity, and year of birth was applied, in addition to questionnaire assessments of own and partner's smoking behavior, educational attainment, and symptoms of anxiety and depression at weeks 17 and 30 of gestation from both pregnancies.

Results: The vast majority did not smoke in either of the pregnancies, and more women quit smoking than relapsed to smoking in their second pregnancy. Among smokers in the first pregnancy, 30.9% quit smoking by their second pregnancy. Women living with a nonsmoking partner or a partner who quit between pregnancies were more likely to quit smoking, as were women smoking occasionally in their first pregnancy. Symptoms of psychological distress and increasing number of years between pregnancies were negatively associated with smoking cessation. Among women not smoking in their first pregnancy, 2.3% did smoke during their second. Living with a smoking partner, low educational attainment, symptoms of psychological distress, and increasing number of years between pregnancies were all associated with smoking during the second pregnancy.

Conclusions: These findings, linking smoking behavior to changes taking place between pregnancies, offer new and additional insight into modifiable risk factors that may help facilitate more targeted smoking cessation interventions for women at the highest risk.