Smoking cessation support and obstetric outcomes in an Irish maternity hospital

Maternal cigarette smoking is a recognised risk factor for maternal and fetal morbidity and mortality and remains a significant problem in the Irish maternity system. Approximately 11% of Irish women will continue to smoke in pregnancy, despite awareness of the negative impact on their pregnancy. Although recommendations exist for the management of pregnant smokers, information on the antenatal care of Irish smokers in pregnancy has not been described. We reviewed the care given to smokers in a large urban maternity hospital.

This is a retrospective cohort study of 100 consecutive smokers and 110 contemporaneous non-smokers who delivered at a large urban maternity hospital of over 8200 births per year in Oct-Nov 2017. Data were obtained from both electronic patient records and chart review to ensure comprehensive capture of outcomes.

In general, mothers who smoked were younger (29yrs vs 33yrs p < 0.001) and of higher parity (1.4 vs. 1.0 p < 0.001) than non-smokers. They were less likely to have a planned pregnancy (44.4% vs 79.6%, p < 0.001) and less likely to have taken pre-conceptual folic acid (22.2% vs 58.3%, p < 0.001). These mothers also had a higher rate of history of illicit drug use, particularly cannabis (19.1% vs 0.9%, p < 0.001) and opiates (16.1% vs 0.9%, p < 0.001). Mental health issues were commoner in smokers with 36.3% describing depression, postnatal depression or bipolar disorder and 34.3% experiencing anxiety disorder or panic attacks. Smoking cessation advice was identified in only 36.5% of smokers and no smokers were referred for smoking cessation interventions. Two thirds of smokers were referred for an additional ultrasound, largely due to suspected fetal growth restriction. Infants of smoking mothers had lower mean birthweights (3.16 kg vs 3.47 kg p < 0.001) and mean birth centile (27th vs 47th p < 0.001) than non-smokers. Twenty eight percent of these infants were small for gestational age, an incidence significantly higher than non-smokers at 13% (p < 0.001).

Maternal cigarette smoking appears to be a largely tolerated risk factor in the population studied, despite being associated with poor obstetric outcomes. We identified an absence of smoking cessation services and a lack of intervention and structure around care pathways.