Smoke-Free Legislation and Adverse Pregnancy Outcomes in England

Abstract

Background: There is a wide array of evidence on the morbidity and mortality associated with smoking and second-hand-smoke on both adults and children. In response to these findings and following the Health Act, 2006, England introduced a new law to make virtually all enclosed public places and workplaces smoke free on July 1, 2007. Aim: To investigate the effect of smoking-free legislation on adverse pregnancy outcomes in England. Methods: A retrospective observational study design is used to analyse routinely collected national Hospital Episode Statistics (HES) maternity data covering the whole of England. All mothers who delivered singleton live-births between 24 to 44 weeks of gestation between January 1, 2005 to December 31, 2009 are included in the analyses (N=1,819,633). Regression discontinuity (RD) model, which is a quasi-experimental model, was employed to analyse the effects of the 2007 UK smoke-free legislation on pregnancy outcomes on birth weight, preterm and small for gestational age. Results: Preliminary results show that in the six months following the smoking-free legislation, low birth weight rates decreased by 5 to 7%, preterm deliveries decreased by 4 to 5%, and small for gestational age rates decreased by 6 to 7%. An overall increase in pregnancies gestational age and babies birth weights was also observed in the same time period. Most of the effects of the legislation on low birth weight, preterm delivery and small for gestational age were most pronounced in babies delivered by women aged 20-29, women living in less deprived areas in the east and south of England. Conclusions: Smoke-free legislation in England is likely to have positively influenced pregnant women's environment with respect to smoke and second hand some exposure. Our analyses are consistent with beneficial effects on pregnancy outcomes apparent within six months of the introduction of this legislation.