Both smoking during pregnancy and secondhand smoke exposure are associated with reduced health outcomes. However, limited consistent evidence exists of risks of secondhand smoke exposure in pregnancy. Currently, inadequate smoking cessation services exist in Irish maternity hospitals. To identify the number of pregnant women smoking during pregnancy and to identify their exposure to secondhand smoke, we conducted a cross-sectional observational pilot study in one regional maternity hospital in Ireland in July/August 2018. Respondents were (1) women attending antenatal clinics and (2) postpartum women before discharge. Variables measured included smoking status of pregnant women and partner status, demographic variables, secondhand smoke exposure, and support for hospital smoke-free policy and development of smoking cessation services. The overall response rate was 42.2% in this study. The response rate was 56.5% (111/196) from postnatal wards and 37.3% (215/577) from antenatal clinics. Over 40% of respondents reported they had smoked during their lifetime. The majority of women (70%) reported quitting smoking before their pregnancy. Few women were active smokers. Almost 40% reported exposure to tobacco smoke in the previous week (38.5%); 16.9% reported living with a smoker, a critical factor in increased risk (Odds Ratio (OR) 3.89, 95% CI = 1.86-8.15, p < 0.001). Approximately 10% of postnatal mothers reported that their newborn would travel home with a smoker. Support for a no-smoking hospital policy was very high as was support for the development of cessation services. No documentation of secondhand smoke exposure for pregnant women or newborns is sought or recorded routinely in the hospital. A systems approach to develop smoking cessation programmes in maternity care should include screening and documenting of secondhand smoke exposure risks for women during pregnancy, and for their newborns at discharge, to improve health outcomes and protect human rights.