. Author manuscript; available in PMC: 2018 Jul 17.

Published in final edited form as: Chem Res Toxicol. 2017 Jun 20;30(7):1376–1383. doi: 10.1021/acs.chemrestox.7b00054

Table 1.

Summary of Smoking Bans and Preterm Birth Studies

First Author	Location of Study	Population	Year of Ban	Details of Smoking Ban	Preterm Birth Definition	Immediate Change in Preterm Birth Rate (overall adjusted)^*	Findings
Page¹⁰	USA: Pueblo & El Paso, CO	470,000	2003	Workplaces and Public places in Pueblo; none in El Paso	Preterm <37 weeks	−23.1% [95% CI: −40.1, −1.3]	Post-ban: Preterm birth rates reduced by 23.1 % in Pueblo compared to El Paso pre-ban
Bharadwaj¹¹	Norway	4,950,000	2004	Restaurants and Bars; Previous ban on Workplaces and Public places	Preterm <36 weeks	−2.55%^** [95% CI: −5.52, 0.42]	Post-ban: Preterm birth rates reduced by 2.55% % in mothers working in bars and restaurants.
Kabir⁸	Ireland	4,580,000	2004	Workplaces and Public places	Preterm <37 weeks	−25% [95% CI: −41.0, −4, 0]	Post-ban: Preterm birth rates reduced by 25%
MacKay⁹	United Kingdom: Scotland	5,300,000	2006	Workplaces and Public places	Among smokers & non-smokers: Mild Preterm <37 weeks; Moderate Preterm <34 weeks; Extreme Preterm <32 weeks	−11.72% [95% CI: −15.87, −7.35]	Among both smokers & non-smokers: Post-ban: Preterm birth rates reduced by 11.72%
					Stratified by: Current Smokers	−5.51% [95% CI: −13.84, 3.63]	Among currently smoking mothers: Post-ban: Preterm birth rates reduced by 5.51%
					Stratified by: Non-smokers	−15.44% [95% CI: 21.02, −9.47]	Among never smoking mothers: Post-ban: Preterm birth rates reduced by 15.44%
Cox⁷	Belgium: Flanders	6,250,000	2006	Phase I: Workplaces and Public places	Preterm <37 weeks; Very Preterm <32 weeks	Overall: −0.59%^** [95% CI: −2.63, 1.49]; Spontaneous: −3.24% [95% CI: −4.40, −2.07]	Phase I Post-ban: Preterm birth rates reduced by 0.59% overall and 3.24% for spontaneous preterm birth.
			2007	Phase II: Restaurants	Preterm <37 weeks; Very Preterm <32 weeks	Overall: −2.28% [95% CI: −4.37, −0.15]; ; Spontaneous: −3.69% [95% CI: −4.81, −2.55]	Phase II Post-ban: Preterm birth rates reduced by 2.28% overall and 3.69% for spontaneous preterm birth.
			2010	Phase III: Bars Serving food	Preterm <37 weeks; Very Preterm <32 weeks	Overall: −1.24%^** [95% CI: −3.05, 0.60]; Spontaneous: −3.36% [95% CI: −4.73, −1.9]	Phase III Post-ban: Preterm birth rates reduced by 1.24% overall and 3.36% for spontaneous preterm birth.
			2010	All Phases	Preterm <37 weeks; Very Preterm <32 weeks	Overall: −3.18% [95% CI: −5.38, −0.94]; Spontaneous: −3.13% [95% CI: −4.37, −1.87]	All phases post-ban: preterm birth rates reduced by 3.18% overall and 3.13% for preterm birth.

p<0.05

^**

not statistically significant; absolute change