Born Into a Smoke-Free World

Smoking ban linked to fewer preemies and lower rates of pregnant moms smoking

(RxWiki News) The effect of tobacco smoke on pregnant women and their developing babies is well-documented, but what if a baby were born into a community where no public smoking was allowed at all?

The first study conducted in the U.S. to compare a city with a smoking ban to a city without one found that fewer pregnant women were smoking and fewer babies were being born early.

"Avoid cigarette smoke while pregnant."

Robert Lee Page, II, a pharmacist in the Department of Clinical Pharmacy at the University of Colorado's Skaggs School of Pharmacy and Pharmaceutical Sciences, led the study to investigate the impact of a public smoking ban on the area's birth outcomes.

Page and colleagues compared two communities that were similar in terms of size, population and geography, except that one had a city-wide public smoking ban and the other did not.

Pueblo, Colorado, was the town with a city-wide smoking ban, implemented as part of an experiment. The comparison community was El Paso County.

Neither town had a smoking ban from April, 2001 until July, 2003, so data was collected for that period as a control from both towns. The period of the smoking ban ran from April, 2004, to July, 2006.

The researchers gathered information on the mothers' smoking rates based on the moms' self-reporting, low birth weight of babies born, and the number of preemies born before 27 weeks of pregnancy.

Low birth weight was counted in two ways, as being under 5.5 pounds and being under 6.6 pounds. Only single births were included in the study, not twins or other multiples.

During the period of the complete study, 6,717 babies were born in the city of Pueblo, and 32,293 were born in El Paso County.

The investigators looked at a wide range of characteristics in both counties before the ban began, including education levels, pregnancy complications and demographic characteristics of the mothers, so they could calculate these starting differences into their results.

The results showed that mothers in Pueblo were 38 percent less likely to smoke after the ban was instituted compared to El Paso County, and the rate of preterm births was 23 percent lower in Pueblo.

There were also fewer babies born with a low birth weight in Pueblo (8.4 percent lower for being under 5.5 pounds and 8 percent for being under 6.6 pounds), though this difference may have been due to coincidence and was not considered significant.

"This is the first evidence in the United States that population-level intervention using a smoking ban improved maternal and fetal outcomes, measured as maternal smoking and preterm births," the authors concluded.

"These data suggest that smoke-free legislation may act as an effective strategy for deterring exposure to both firsthand and secondhand cigarette smoke in pregnant mothers and their newborns," they wrote.

The study appeared online ahead of print March 8 in the Journal of Women's Health. It was not funded by an outside source, though the authors acknowledged the Colorado Department of Public Health and Environment Division of Health Statistics in their paper. They reported no conflicts of interest.

Review Date: 
May 10, 2012