A new study in Denmark shows that women who quit smoking right before or soon after conception give birth to babies of similar birth weights, on average, as nonsmokers.
Babies whose mothers keep smoking during pregnancy are more likely to be born at a low weight.
“The big thing to get out of this study is that quitting early in pregnancy is as helpful in respect to the birth weight of your baby as never having smoked while you were pregnant,” Dr. Amber Samuel, a maternal-fetal medicine expert at Emory University School of Medicine in Atlanta, said, who was not involved in the study.
“I think that can be an inspiration to moms who are looking to make a change in their lives.”
Babies born to mothers who smoked during or after pregnancy are at three to four times greater risk of dying from sudden infant death syndrome, or “crib death.” Children exposed to secondhand smoke also have more ear infections, pneumonia, bronchitis, asthma and other health problems.
The new study involved 1,774 women who were participants of the “Smoke-free Newborn” study conducted in Copenhagen, Denmark, between 1996 and 1999.
Twice during pregnancy, researchers asked women about their smoking status. Their saliva was also tested for cotinine—created when nicotine is broken down in the body.
About 38 percent of the participants were smokers before becoming pregnant, and half of them quit right before or soon after, according to Dr. Line Rode of Copenhagen University Hospital and colleagues.
During pregnancy, nonsmokers gained almost 30 pounds, on average, smokers gained 29 pounds and quitters gained 35 pounds.
Among women who quit smoking, 8 percent had babies born below the 10th percentile for birth weight, based on general Scandinavian records, compared to 22 percent of smokers’ babies.
Babies with low birth weight are at higher risk for infections, breathing and respiratory disorders, delayed growth and social development and learning disabilities.
One year after giving birth, half of quitters were able to stay off cigarettes. Nonsmokers and relapsed quitters both gained between 1.5 and 2 pounds post-pregnancy, successful quitters gained 7 pounds and smokers lost about half a pound, according to findings published in Obstetrics and Gynecology.
“One strength of the study is that it tried to ferret out whether women who say they quit smoking actually did quit,” Samuel said.
On the other hand, she said these findings may not apply to the current U.S. population. “There were very few obese women in this study,” Samuel said.
She added that most women in this study did not gain enough weight to offset the long-term benefits of not smoking.
Samuel also noted that it’s not possible to pinpoint just when a woman needs to quit smoking in order to see benefits for her baby, since the researchers did not analyze their results based on when, exactly, women quit smoking.
Source: Obstetrics and Gynecology