Smoking while pregnant is on the decline in Colorado, but still remains one of the leading preventable causes of low birth weight in newborns, a study by the Colorado Department of Public Health and Environment (CDPHE) said Wednesday.

One in 14 low-weight births between 2007-2009 were due to smoking, a decrease from almost one in eight low-weight births a decade earlier.

The CDPHE said that while smoking during pregnancy was decreasing, there was no improvement on the amount of women gaining enough weight during pregnancy, another leading factor in low birth weight. Jillian Jacobellis, the Prevention Services Division director at the CDPHE, said that smoking during pregnancy or not gaining enough weight both cause a significant risk of a newborn weighing less than 5 pounds, 8 ounces at delivery.

“These low birth-weight babies are at risk for disabilities, complications requiring longer hospital stays and treatment in intensive care units, and even death. Public health interventions that address these issues are necessary to reduce these numbers,” said Jacobellis.

Women of a normal weight for their height are advised to gain between 25 and 35 pounds; underweight women, 28 to 40 pounds; overweight women, 15 to 25 pounds and obese women, 11 to 20 pounds.

To calculate what your ideal weight gain during pregnancy would be, click here

After finding in the late 90s that almost 12 percent of Colorado women smoked during pregnancy, the CDPHE started a public health campaign to encourage women to quit smoking. In the latest study, the CDPHE said that the number of women smoking during pregnancy decreased to 8.7 percent. Jacobellis credits the public health campaigns, as well as tax increases to tobacco products and the Clean Indoor Act—which apply to all smokers—in helping the numbers to drop.