BACKGROUND
This longitudinal study examined the profile and pregnancy-related behaviours of women who reported smoking in two successive pregnancies when they presented for prenatal care in a large maternity hospital.

METHODS
Using the hospital electronic medical records, women who delivered two successive singleton pregnancies during the years 2011-15 were analyzed. Standardized data were computerized by a midwife at the first prenatal visit, following delivery and before discharge.

RESULTS
Over the 5 years, 6647 women delivered twice. Overall 5754 (86.6%) were persistent non-smokers in both pregnancies, 609 (9.2%) were persistent smokers in both pregnancies and between pregnancies 202 (3.0%) quit and 82 (1.2%) started smoking. Compared with persistent non-smokers, persistent smokers had higher rates of reported illicit drug use, alcohol consumption and psychological problems and lower rates of planned pregnancy, folic acid supplementation and breastfeeding in both pregnancies (all P < 0.001). In persistent smokers, folic acid supplementation practices deteriorated and illicit drug use increased in the subsequent pregnancy.

CONCLUSIONS
We found that approximately one in 10 women smoked in two consecutive pregnancies. Furthermore, compared with non-smokers, persistent smokers were more likely to report other health behaviours associated with adverse pregnancy outcomes and may require additional multidisciplinary support.