Smoking while pregnant doubles risk of sudden unexpected infant death, study finds

Smoking during pregnancy — even just one cigarette a day — doubles the risk of sudden unexpected infant death (SUID), according to a new study.

The Seattle Children’s Research Institute worked in collaboration with Microsoft data scientists for their study, published in the journal Pediatrics Monday. Their research found that the chances of SUID increased by 0.07 per cigarette for women who smoked between 1 to 20 cigarettes a day.

Researchers also estimated that 800 deaths of the 3,700 total SUIDs every year in the U.S. could be prevented if women abstained from smoking during pregnancy. That would lower the SUID rates by 22 percent.


“With this information, doctors can better counsel pregnant women about their smoking habits, knowing that the number of cigarettes smoked daily during pregnancy significantly impacts the risk for SUID,” Dr. Tatiana Anderson, a researcher in Seattle Children’s Center for Integrative Brain Research and lead author on the study said in a statement.

“Similar to public health campaigns that educated parents about the importance of infant sleep position, leading to a 50 percent decrease in sudden infant death syndrome (SIDS) rates, we hope advising women about this risk will result in less babies dying from these tragic causes," Anderson continued.

Using data from the Centers for Disease Control and Prevention (CDC), scientists analyzed the habits of mothers who smoked for all live births from 2007 to 2011, which covered about 20 million live births.

Of those live births, more than 19,000 deaths over the four-year period were attributed to SUID, caused by sudden infant death syndrome (SIDS), an unknown cause or accidental suffocation and strangulation in bed, researchers found.


They also found that there was a 23 percent decrease in the risk of SUID for women who completely quit smoking and a 12 percent decrease in risk for women who reduced the number of cigarettes they smoked by the third trimester.

Mothers who smoked three months before pregnancy but quit in the first trimester still had a higher risk of SUID than women who don’t smoke, the study found.

“The most important takeaway is for women to understand that quitting smoking before and during pregnancy by far results in the greatest reduction in SUID risk,” Anderson said.

“For pregnant women unable to quit entirely, every cigarette they can eliminate will reduce the odds of their child dying suddenly and unexpectedly from SUID,” she added.