Changes in smoking behavior between first and second pregnancies.

Objective: To assess changes in maternal smoking behavior at the second pregnancy.

Methods: First and second birth certificates were matched for 5241 white and black mothers in Kansas City, Mo, who had singleton births between 1994 and 2003.

Results: The pregnancy-smoking quit rate was 24.9%, and the pregnancy-smoking initiation rate was 4.8%.

Conclusion: Twenty-five percent of women who smoked and 5% of women who did not smoke during their first pregnancy changed their behavior during their second pregnancy. These findings reflect a minimal net shift in pregnancy-smoking between pregnancies and support the importance of persistent antismoking socialization that is independent of a pregnant woman's previous pregnancy-smoking status.