Change in smoking status during two consecutive pregnancies: a population-based cohort study

Area of Science:

• Reproductive Health
• Public Health
• Epidemiology

Background:

• Tobacco smoking during pregnancy poses significant risks to both maternal and infant health.
• Understanding changes in smoking behavior between consecutive pregnancies is crucial for developing effective interventions.

Purpose of the Study:

• To examine the patterns of change in tobacco smoking between a woman's first and second singleton pregnancies.
• To identify factors associated with continuing to smoke, quitting smoking, or initiating smoking in the second pregnancy.

Main Methods:

• A population-based cohort study was conducted in New South Wales, Australia, from 2000 to 2010.
• Data from 183,385 women with first and second singleton pregnancies were analyzed using descriptive and multivariable logistic regression.
• Perinatal data were linked with hospital admission records to assess smoking status changes and associated factors.

Main Results:

• Among women who smoked in their first pregnancy, 33.5% quit by the second. Conversely, 3.6% of non-smokers in the first pregnancy initiated smoking in the second.
• Factors associated with quitting or not starting included older maternal age (≥25 years), marriage, non-English speaking background, private obstetric care, and higher socioeconomic status.
• Specific pregnancy complications like gestational hypertension, large-for-gestational-age infants, and stillbirth were linked to higher quit rates among smokers, while small-for-gestational-age infants or special care nursery admissions were linked to lower quit rates.

Conclusions:

• A significant proportion of women continue smoking across consecutive pregnancies, even after experiencing adverse outcomes.
• Interventions should be intensified and targeted towards women identified as high-risk for continued or initiated smoking during pregnancy.