Though the authors note their study is limited to "conservative smoking estimates" because their data set does not include environmental smoke exposure during pregnancy or postpartum, including fathers who smoke, they affirm that maternal smoking has been linked to premature deaths in infants. Now, researchers from Seattle Children's Hospital are exploring how smoking during pregnancy can lead to fatal consequences.
The first findings to result from a collaboration between Seattle Children's Research Institute and Microsoft data scientists provides expecting mothers new information about how smoking before and during pregnancy contributes to the risk of an infant dying suddenly and unexpectedly before their first birthday. Quitting smoking was associated with a 23 percent reduction in SUID risk.
"We hope advising women about this risk will result in less babies dying from these tragic causes".
According to experts, self-reported statistics show that about 338-thousand women admit to smoking during pregnancy each year and that more than half of them are unwilling or unable to stop.
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.
Sudden unexpected infant death defined as (SUID).
Quitting smoking before pregnancy reduced the risk of SUID by over 20 percent, while scaling down the cigarette habit during pregnancy reduced the risk by over 10 percent.
On the other hand, mothers who smoked three months before getting pregnant but quit in the first trimester still had a higher risk of SUID when compared to non-smokers.
The harmful effects of smoking are not unknown.
After the first cigarette per day, the study found the risk of SUID increased by 0.07 for each additional cigarette smoked up to 20 per day, at which point it plateaued-and at which point it's triple the risk of women who don't smoke, the Seattle Times reports.
"Since many women who smoke during pregnancy continue to smoke after they deliver, it is a little hard to separate out the effects of prenatal and postnatal cigarette smoke exposure", said Dr. Michael Goodstein, division chief of WellSpan Health Neonatology in York, Pennsylvania. "When these infants sleep, these basic functions may be compromised resulting in SIDS". "In babies that have been smoke exposed, their wake up system does not trigger as soon as it should and we think this could be partly why these babies are more likely to die (of) SIDS".