Any smoking before or during pregnancy is unsafe, study shows

Light smoking is also tied to poor birth outcomes, even if the mother quits during pregnancy.

Smoking even one or two cigarettes a day before or during pregnancy can lead to serious health problems for newborns, according to a new analysis of more than 12 million families.
Globally, an estimated 1.7 per cent of pregnant women smoke, though that rate is 8.1 per cent in Europe and 5.9 per cent in the Americas. Smoking during pregnancy can negatively affect the newborn’s health, increasing their risk of preterm birth, low birth weight, restricted infant growth, and death.
In the study, which was published in the Journal of Epidemiology & Community Health, researchers analysed the relationship between smoking and major neonatal health complications such as needing assisted ventilation immediately after birth, being admitted to the neonatal intensive care unit (NICU) with ventilation, suspected sepsis, seizures, or neurological dysfunction.
Overall, about 9.5 per cent of babies experienced these issues. But they were 27 per cent more likely to have several of these complications if their mother smoked before pregnancy, and 31 per cent more likely if she smoked at any point during pregnancy, researchers found.
While researchers have long known about the poor outcomes tied to smoking during pregnancy, the new study indicates that even light smoking is unsafe, including in the months before pregnancy.
“Any smoking at all during pregnancy has an impact on infant outcomes,” Caitlin Notley, who leads the addiction research group at the University of East Anglia in England, told Euronews Health. She was not involved with the study.
The analysis included nearly 12.2 million mother-infant pairs in the US, and found that the health risks held up even after researchers adjusted for other factors, such as age, ethnicity, and weight. Women with high blood pressure or diabetes were not included in the study.
Among the mothers in the study, 9.3 per cent smoked before pregnancy, while 7 per cent smoked in the first trimester, 6 per cent smoked in the second trimester, and 5.7 per cent smoked in the third trimester.
Neonatal outcomes were worse among those who smoked later into their pregnancies, the study found, but women who stopped smoking during pregnancy were still at a higher risk of poor neonatal outcomes compared with those who didn’t smoke at all.
Risks were also higher for heavy smokers. The children of women who smoked 20 or more cigarettes per day were 29 per cent more likely to be admitted to intensive care, the study found. Yet those who smoked only one or two cigarettes per day still saw a 13 per cent higher risk of NICU admission.
“It’s quite clear that cutting down, particularly during pregnancy, isn’t enough,” Notley said, emphasising the need for “complete cessation” of smoking to protect infant health.
Pregnant women may find it harder to quit smoking because nicotine metabolism speeds up during pregnancy, meaning the body absorbs it more quickly, Notley said.
She said pregnant women trying to quit can try nicotine replacement therapies, such as nicotine gum, and opt for a higher dose if they find themselves still turning to cigarettes.
They can also try replacing traditional cigarettes with e-cigarettes, which may contain nicotine but no tobacco. Research is mixed on the effects of vaping on pregnancy outcomes.
“It’s a harm reduction approach of doing anything you can, basically, to support women to quit smoking,” Notley said.