Background: Maternal smoking is a key modifiable risk factor in preventing adverse pregnancy outcomes such as intrauterine growth restriction, preterm birth and stillbirth.

Aim: This observational study examined annual trends of maternal smoking reported at the first prenatal visit in women who delivered in a large university maternity hospital for the 5 years 2011–2015.

Methods: We examined clinical and sociodemographic data computerised routinely for women who presented for prenatal care at the hospital between 2011 and 2015. Multinomial logistic regression was used to determine the maternal characteristics, health behaviours and psychiatric history associated with smoking behaviours.

Results: Of the 42,509 women the mean age was 31.4 ± 5.5 years, mean Body Mass Index (BMI) was 25.6 ± 5.1 kg/m2, and 39.5% were nulliparas. Overall, 52.6% reported they had never smoked, 34.9% were ex-smokers, 10.5% smoked ≤10 cigarettes per day, 1.9% smoked ≥11 cigarettes per day and 0.1% smoked e-cigarettes. Between 2011 and 2015 the prevalence of maternal cigarette smoking decreased from 14.3 to 10.9% (P < 0.001). Smoking during pregnancy was most strongly associated with younger age, multiparity, unemployment, unplanned pregnancy, a history of psychiatric problems, alcohol intake and illicit drug usage.

Conclusions: The number of women who reported smoking at the first prenatal visit decreased annually. Amongst women who continue to smoke during pregnancy, there is a clustering of adverse lifestyle behaviour and psychological problems that may need to be addressed if smoking cessation interventions are going to succeed in improving fetal programming.