Researchers analyzed data from more than 8,500 mothers-to-be who took part in an annual government health survey. It found a 2.5 percent rise in smoking rates among pregnant women with depression between 2002 and 2014.
Smoking rates among other groups fell during that time, according to the study published online in the October issue of the journal Drug and Alcohol Dependence.
"An increase in smoking rates in any population is concerning given the general overall downward trends we are seeing today," said study leader Renee Goodwin. She's an adjunct associate professor of epidemiology at Columbia University's Mailman School of Public Health.
More than a third of pregnant women with depression smoke, compared with 1 in 10 who are not depressed, according to the study.
Goodwin said the link between depression and prenatal tobacco use has increased over time, suggesting that depression is an important -- but rarely treated -- barrier to quitting smoking.
She noted that smoking during pregnancy is more common among women who are unmarried, less educated and have lower incomes. "Notably, these are also groups who often have less access to prenatal care," she added in a Columbia news release.
Goodwin said many women may be unaware that depression is interfering with their ability to stop smoking and may need extra help to quit.
"Public health campaigns to educate people about the importance of quitting smoking during pregnancy is highly recommended. Treatment for depression in conjunction with smoking cessation efforts may also be the critical component to help women succeed in quitting," Goodwin concluded.