Babies of pregnant smokers quadruple the chances of being underweight.
Researchers at the University of Cambridge have found that women who smoke during pregnancy are 2.6 times more likely to give birth prematurely than non-smokers, more than double what previous studies estimated. Their study, published yesterday in the International Journal of Epidemiology, also found that when a pregnant woman smokes, the baby is four times more likely to be small for its gestational age, which poses a greater risk of serious complications, such as breathing difficulties and infections. On the other hand, they found no evidence that caffeine intake affects fetal development as until now believed.
Pregnant women, or even those who aspire to become pregnant, have long been advised to quit smoking because tobacco use has been associated with reduced fetal growth, premature birth and low birth weight, and even the likelihood of of preeclampsia (high blood pressure during pregnancy). There is also evidence that pregnant women’s exposure to tobacco, even as a passive smoker, increases the risk of neurodevelopmental alterations and translates into worse long-term neurological outcomes.
But the studies that analyze these links between smoking and complications during pregnancy are mostly based on self-reported data, on what pregnant women say they consume, and gynecologists know that a high percentage smoke secretly or relativize their tobacco consumption. “Despite everything that is known about its damage to fetal development, there is still a high consumption of tobacco and alcohol during pregnancy and many women are unaware that only two cigarettes also count, that every puff they take is given by the fetus.” “, emphasizes Eduard Gratacós, director of BCNatal, specialist in pregnancy and fetal disease.
For all these reasons, the Cambridge researchers decided to look for a more objective measure of the actual exposure of pregnant women to tobacco and caffeine by observing the levels of metabolites in the blood, the chemical remains that are created when the body processes tobacco and caffeine. .
To evaluate exposure to cigarette smoke, they monitored cotinine levels in blood samples from 914 women taken four times during pregnancy. And they found that those with consistent exposure to smoking were 2.6 times more likely to experience spontaneous preterm birth than those who were not exposed (the previous estimate from a meta-analysis of studies was 1.27, less than half). . In addition, they observed that they quadrupled the probability of experiencing fetal growth problems. Specifically, the babies of smokers weighed an average of 387 grams less than those of non-smokers, which is more than 10% less than the average weight of a newborn, and low birth weight is related to a greater risk of problems in development and poorer future health. In contrast, they found no evidence that smoking affects the risk of preeclampsia.
“We have known for a long time that smoking during pregnancy is not good for the baby, but our study shows that it is much worse than previously thought,” explained the head of Obstetrics and Gynecology at the University of Cambridge, Gordon Smith, who encourages pregnant women and women planning a pregnancy to stop smoking so as not to put their baby at risk of serious complications from growing too slowly in the womb or being born too soon.
Regarding the impact of caffeine, the researchers analyzed the presence of the metabolite paraxanthine and found little evidence of an association between high caffeine intake and adverse outcomes during pregnancy or childbirth. Gratacós assures that this is one of the most striking results for perinatal health specialists. “Other studies linked poor perinatal outcomes to caffeine consumption, but this research – which is very well done – shows that coffee is a confounding variable, which when you control and adjust for others (such as whether the mother smokes or the type of life she leads) carries), it turns out that caffeine is not associated with a greater risk,” he explains. The Cambridge research has found little evidence that caffeine affects fetal development. Mayte Rivers
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