Which is worse in pregnancy: snuff or cigarettes?

Babies born to snuff-using mothers were more likely to have breathing problems than those whose moms smoked cigarettes while pregnant, in new data from Sweden.

Snuff - ground tobacco that is high in nicotine but doesn't generate the same additional chemicals as cigarette smoke because it's not burned - is generally assumed be safer than cigarettes, said the authors of the new study.

That's still the case for many people - but it's not a good option for pregnant women, according to Dr. Anna Gunnerbeck, the lead researcher from the Karolinska Institute in Stockholm.

The smokeless tobacco "may have a little bit different effect than smoking, because smoking has the combustion products, but it's still not safe during pregnancy," Gunnerbeck told Reuters Health.

It's possible the same may apply to nicotine gum and patches, which some doctors recommend to women trying to stop smoking during pregnancy, researchers said. Gunnerbeck and her colleagues got their data from records of about 610,000 babies born in Sweden between 1999 and 2006.

They compared information gathered from moms when they were a few months pregnant - including about snuff and cigarette use - with babies' hospital records. Specifically, the researchers were looking for a diagnosis of "apnea," which occurs when a newborn stops breathing, sometimes accompanied by an irregular heartbeat. One or two in every 1,000 babies born to moms who didn't use snuff or cigarettes developed apnea, according to the results published in Pediatrics.

For babies whose moms had lit up during pregnancy, that risk increased by about 50 percent. And for those whose moms used snuff, the rate was more than twice as high as in babies born to mothers who didn't use any kind of tobacco.

When the researchers took into account how early babies were born - prematurity has been linked to both maternal smoking and breathing problems in newborns - smoking alone didn't have any extra effect on the risk of apnea.

But apnea was still more common when moms used snuff, regardless of whether babies were born early or on time. Many babies with apnea will get a bit of extra care soon after birth and be fine, Gunnerbeck said.

But it's also possible that those babies are more likely to have breathing problems, including sleep apnea, when they're older. And apnea may put a kid at higher risk of infection later. While snuff use is more common in Sweden than elsewhere, pregnant women in other countries may also use nicotine-containing products, such as gum and patches, thinking they're safer than smoking during pregnancy, researchers said.

"They're raising the concern that Swedish snuff, because it's largely nicotine, can be a surrogate for nicotine replacement therapy during pregnancy, that it might have untoward effects," said Dr. Michael Weitzman, who studies smoking in pregnancy at the New York University Medical Center and was not involved in the new research.