Children of mothers who continue to smoke during pregnancy have measurably smaller brains by age 10. This is the conclusion of Erasmus MC scientists in a study conducted last week popped up. The study underlines that smoking during pregnancy can have negative consequences for the child until long after birth.
“This provides new insights,” says Corine Verhoeven, professor of obstetrics science at the University of Nottingham. “It is known that smoking during pregnancy poses a risk for long-term reduced health in children, but to my knowledge this is the first time that effects on brain development at this age have been demonstrated in this way.”
By 2021, eight percent of pregnant women in the Netherlands smoked at some point during their pregnancy, according to figures published by the Trimbos Institute. collected. 4.8 percent smoked during the entire pregnancy. That percentage has fluctuated around the same value for five years. Women with a low income and low education continue to smoke more often during pregnancy than women with a higher socio-economic status.
Difficult to investigate
The risks of smoking for unborn and newborn children are often researched and widely known. For example, smoking pregnant women have a higher risk of miscarriage or premature birth. Newborns of smoking mothers have a smaller head circumference and a lower birth weight at birth.
But the consequences of smoking during pregnancy later in the child’s life are more difficult to investigate. The Rotterdam brain size study is part of the Generation R study. It follows the development and health of growing children in Rotterdam over several years.
Researchers analyzed the data of 2,704 women and their children. Participating women who were pregnant between 2002 and 2006 were asked whether they smoked during their pregnancy. 364 women in this group (13.5 percent) continued to smoke during pregnancy. 238 women (8.8 percent) gave up as soon as they found out they were pregnant. With an MRI scan, the researchers determined brain size and structure of children when they were between 9 and 11 years old.
The children of smoking mothers not only had a smaller total brain volume, but also less white matter (for signal transmission between brain cells) and gray matter (where most brain cells reside) and less deep convolutions (gyri) than mothers who never smoked or after smoking. were discontinued in the first trimester. In this study, the Rotterdammers did not investigate whether the children of smoking mothers also experienced cognitive disadvantages. “But in general you can say that children with smaller brains have a lower IQ and more behavioral problems,” said Runyu Zou, epidemiologist and lead author of the article.
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Brain Development
The researchers emphasize that there were no differences between children of mothers who never smoked and mothers who quit early in pregnancy. Only later in pregnancy does brain growth and development really get going. “Even if a woman has smoked in the first 10 weeks of pregnancy, it still makes sense to quit,” says Zou.
“So young men and women would rather stop before they try to get pregnant,” says Corine Verhoeven. “It is precisely at the beginning of the pregnancy that all the important organs are formed. In short, if you want to have children: first stop smoking, then use contraception.”
Do differences in brain size persist throughout life? “We cannot say that on the basis of this research,” says Zou. “Perhaps differences will improve later in life. The brain is a plastic organ.” Zou and his colleagues plan to repeat the study when the Generation R participants are adolescents and young adults.