Even a cup of coffee every day could be too much for pregnant women (Image: Thinkstock)
Reading aloud If a woman is pregnant, she has to do without a lot: alcohol and smoking are taboo, other drugs anyway. But how about the coffee or the coke? Can the caffeine in these drinks also harm the unborn child? So far, the results have been contradictory. A study of almost 60, 000 pregnant women in Norway now provides more clarity. She shows: Although the coffee drinker does not have to worry about premature birth, she is more likely to have a baby that is too small and light for his age.

There has been some evidence for some time that not only certain medicines and drugs, but also the diet in pregnancy have an impact on the development of the child. Although many substances are filtered out of the placenta before they can reach the body of the unborn child with the blood, but not all: "Similar to oxygen and many nutrients, caffeine passes freely through the placenta, " said Verena Sengpiel of Sahlgrenska University Hospital in Gothenburg and her colleagues. However, the body of the child still lacks the enzymes that break down the caffeine in adults. Previous studies have already shown that the activator of fetuses accumulates primarily in the brain tissue.

How much caffeine is harmful?

One of the reasons why the World Health Organization (WHO) recommends that pregnant women take no more than 300 milligrams of caffeine per day, while the recommendations of the health authorities in the USA and Norway are even lower at 200 milligrams per day. To absorb this amount, it is enough, a large cup of coffee, three cups of black tea or a liter of coke to eat - not very much. However, what consequences it has when a pregnant woman indulges herself in this cup of coffee, was previously unclear, as the researchers report. Studies that looked at the impact of caffeine on the risk of miscarriage and premature birth or decreased fetal growth yielded conflicting results.

To clarify these contradictions, Sengpiel and her colleagues have looked at a particularly large number of pregnant women for their study. They evaluated data from nearly 60, 000 women in the Norwegian Mother and Child Cohort Study, who were interviewed at the 17th, 22nd and 30th week of pregnancy about their consumption of caffeine-containing beverages such as coffee, black tea or cola. The study also included weight, health status and age of birth of the children.

No premature birth, but slimmer babies

The result is at least for some negative effects the all-clear: "We found no connection between the caffeine consumption and a premature birth, " says Sengpiel. Miscarriages or other serious complications were no more common in women who consumed much caffeine than pregnant women, who were well below the recommended daily allowances. However, an unrestrained coffee or cola treat was not completely without consequences: The more caffeine the mothers had in their pregnancy, the more likely it was that their child would be behind the normal birth weight. display

On average, when the mother consumed 100 milligrams of caffeine per day - less than a cup of coffee - her child weighed between 21 and 28 grams less at birth than the expected 3, 600 grams and was also smaller than normal. Not even 30 grams seem very much at first glance. However, as the researchers explain, small differences may play a major role in birth weight. Studies have shown that children who were very small at birth were more likely to have health problems both in childhood and adulthood than are newborn babies.

"Our findings may therefore be of clinical relevance, as they show that even caffeine intake below the recommended guidelines increases the risk of low birth weight, " say Sengpiel and her colleagues. Although it is not yet clear whether the weight loss caused by caffeine will have a negative effect on the later life of children. However, as long as there is no clarity, women should reduce their consumption of coffee, tea or coke during pregnancy as much as possible, according to the scientists.

Verena Sengpiel (Sahlgrenska University Hospital, Gothenburg) BMC Medicine © science.de - === Nadja Podbregar

© science.de

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