Objectives: To examine modifiable maternal health behaviours during pregnancy, including folic acid use peri-conceptually, smoking and alcohol consumption patterns, and relate these factors to maternal postnatal infant feeding practices.

Materials and Methods: A prospective observational study involved the recruitment of 539 pregnant women from a Dublin maternity hospital. Following application of exclusion criteria, 450 mothers were followed up at 6 weeks and 6 months postpartum. Quantitative data on folic acid use, as well as mothers’ smoking and alcohol consumption patterns during pregnancy were collected from the antenatal questionnaire. Maternal postnatal infant feeding practices (breastfeeding/weaning data) were recorded from the 6 week and 6 month interviews.

Results: In all, 94 (20.9%) mothers smoked and 159 (35.3%) consumed alcohol during pregnancy. Less than half of the sample (44.4%) reported to taking a specific folic acid supplement at the recommended time peri-conceptually (i.e. pre-conception to 1 month post conception). After adjustment, mothers ≤ 24 years were more likely to have smoked during pregnancy (OR 3.56, 95% CI: 1.32-9.57) and to have not taken folic acid at the recommended time (OR 4.0, 95% CI: 1.64-9.77). Smoking during pregnancy was associated with lack of breastfeeding initiation (OR 3.04, 95% CI: 1.59-5.82), while mothers who did not take folic acid at the recommended time were 82% (OR 1.82, 95% CI: 1.05-3.13) more likely to have added non-recommended condiments (e.g. gravy) to their infants’ foods.

Conclusions: Public health campaigns that aim to improve health behaviours during pregnancy should specifically target younger mothers’ ≤ 24 years. Interventions to increase compliance with optimal infant feeding practices postpartum should consider the antenatal provision of infant feeding advice targeted towards mothers who smoke during pregnancy and those who do not take folic acid at the recommended time peri-conceptually.