The Lancet Global Health journal published an article in June 2018 stating that Ireland has the highest prevalence in the world of smoking in pregnancy. In November, they published this response from Dr Patrick Doorley and Dr Joan Hanafin, ASH Ireland.
Smoking and pregnancy in Ireland
Pat Doorley and Joan Hanafin
In their paper “National, regional, and global prevalence of smoking during pregnancy in the general population: a systematic review and meta-analysis”, Shannon Lange and colleagues report the results of a systematic review and meta-analysis of the scientific literature from 1985-2016 to estimate the prevalence of smoking during pregnancy by country, WHO region, and globally. Smoking during pregnancy leads to adverse effects for women and children and this much-needed report is welcome. Estimates for smoking during pregnancy were calculated via meta-analysis for 43 countries and via statistical modelling for 131 countries and, at 38%, Ireland was reported to have the highest estimated prevalence of all countries.
We enter a note of caution in relation to the figure for Ireland. The five studies (1992, 1996, 2006, 2008, 2011) used to calculate estimates for Ireland had small sample sizes (n=100; 127; 151; 450; 1011), and the two very high prevalence rates (62% and 60.6%) were published in 1992 and 1996 respectively. In recent decades, Ireland has introduced a suite of tobacco control measures leading to substantial decreases in smoking prevalence in the general population and among pregnant women, specifically as a result of the 2004 Smoking Ban. Smoking prevalence for women in Ireland was 32% in 1998 and had decreased to 14.7% in 2017, although it was highest in the 25-34 year age group at 26.1%.
Two recent Irish studies (2012, 2017)   from the time period of the study, with large sample sizes indicate that smoking prevalence in pregnancy is greatly less than the estimated 38% and continues to fall annually. Data from the national longitudinal study Growing Up in Ireland reported by McCrory and Layte (2012) show that 28% of mothers whose children were born between 1997 and 1998 reported that they smoked during pregnancy, and this fell to 18% of mothers whose children were born in 2007. A study of over 42,500 women who passed through the Coombe maternity hospital in Dublin (Reynolds et al. 2017) recorded annual decreases in smoking during pregnancy, with prevalence dropping from 14.3% to 10.9% between 2011 and 2015.
The decrease in smoking during pregnancy is a positive development for public health policy in Ireland but further efforts are needed, especially among disadvantaged populations, if smoking-related risk to pregnant mothers, their infants and children is to be further reduced.
Patrick Doorley & Joan Hanafin, Submitted June 2018; Published November 2018 in The Lancet Global Health
 Lange, S, Probst, C, Rehm, J, and Popova, S. (2018). National, regional, and global prevalence of smoking during pregnancy in the general population: a systematic review and meta-analysis. (published online May 30.) Lancet Glob Health. 2018; http://dx.doi.org/10.1016/S2214-109X(18)30223-7
 Kabir, Z, Daly, S, Clarke, V, Keogan, S, and Clancy, L. (2013). Smoking Ban and Small-For-Gestational Age Births in Ireland. PLoS ONE, 8(3): e57441. doi:10.1371/journal.pone.0057441
 Brugha, R., Tully, N., Dicker, P., Shelley, E., Ward, M. and McGee, H. (2009) SLÁN 2007: Survey of Lifestyle, Attitudes and Nutrition in Ireland. Smoking Patterns in Ireland: Implications for policy and services, Department of Health and Children. Dublin: The Stationery Office. p.8. https://health.gov.ie/wp-content/uploads/2014/03/slan_smokingreport.pdf. Accessed 24th October 2018.
 McCrory, C. & Layte, RJ. (2012). Prenatal Exposure to Maternal Smoking and Childhood Behavioural Problems: A Quasi-experimental Approach. Journal of Abnormal Child Psychology, 40(8): pp. 1277-1288.
 Reynolds, CME, Egan, B, McKeating, A, Daly, N. Sheehan, SR and Turner, MJ. (2017). Five year trends in maternal smoking behaviour reported at the first prenatal appointment. Irish Journal of Medical Science, 186(4), pp. 971-979.