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Pregnant people should avoid caffeine, research suggests

Pregnant people should avoid caffeine, research suggests

Dining keys

  • Caffeine consumption during pregnancy could increase the risks for both a healthy pregnancy and fetal development, according to a recent meta-analysis.
  • The situation is especially acute during the third trimester, because caffeine stays in the body longer due to changes in maternal metabolism.
  • Despite widespread recommendations for moderation, some experts believe that no amount of caffeine during pregnancy is safe.

Regular caffeine consumption could increase the risks during pregnancy, including possible miscarriages and changes in fetal development, suggests a new research published in BMJ Evidence-based medicine . .

Although current health advice assumes that moderate caffeine consumption during pregnancy is safe, the author of the recent meta-analysis found evidence convincing enough to conclude that pregnant women and pregnant women should avoid caffeine altogether.

High risks

For analysis, Jack James, dr , a professor of psychology at the University of Reykjavik in Iceland, has looked at 48 studies focusing on maternal caffeine use over the past two decades. It was found that 32 of them suggested an increased risk of caffeine in four main categories: .

  • Spontaneous abortion
  • The birth of a still child
  • Low birth weight
  • Acute childhood leukemia

Although some previous studies have considered preterm birth an additional risk, James has not found enough evidence to add this to the list.

How caffeine works during pregnancy

To understand the potential harms of caffeine on the fetus, James writes that it is important to look at the main mechanisms of action that come with caffeine consumption. Whether in the form of a drink or food, caffeine easily crosses the placental barrier, exposing the fetus to the drug, James notes. .

This has been proven by other research, especially a study published in April in European Journal of Nutrition who analyzed hair samples from newborns and found traces of caffeine consistent with the amount mothers consumed during pregnancy.

The study indicated that the higher the caffeine consumption, especially in the third trimester, the higher the amount of newborn hair samples, providing an indication of cumulative exposure to fetal caffeine. .

That third-quarter approval is particularly important, James writes. During pregnancy, a woman’s metabolism changes, which means she can eliminate caffeine from her system in the first trimester in a similar way to before she becomes pregnant. But as the pregnancy progresses, the elimination rate drops to about half in the second trimester and only a third in the last trimester.

As a result, the half-life of caffeine increases from the usual adult rate of about five hours in the first trimester to about 18 hours in the 38th week of pregnancy, says James. As the substance stays in the body longer, the risk to the fetus increases.

The effect of caffeine on newborns (and mothers)

Previous research in the late 1980s and early 1990s indicates that caffeine births in their systems affect newborns, including symptoms of caffeine withdrawal.such as sleep disturbances, irritability, increased frequency of irregular heartbeats, breathing problems, more vomiting and a higher risk of tremors, similar to babies of mothers taking narcotics. .

Chronic exposure to chemicals during pregnancy is a cause for concern – the need to be careful with caffeine is imperative.

– JACK JAMES, doctor

The good news, according to one of the oldest studies, was that the symptoms resolved on their own, similar to caffeine withdrawal in adults. But the less stellar news in the recent meta-analysis is the risks during pregnancy, says James, noting that although caffeine is widely consumed worldwide, it is still considered a drug..

«Chronic exposure to chemicals during pregnancy is a concern – caution is imperative with caffeine,» says James, adding that substantial evidence for an association between maternal caffeine consumption and mixed and negative pregnancy outcomes should trigger some alarm.

With some studies, says James, there is no consumption threshold in which negative results do not exist to some extent.In other words, caffeine could be the exception to the «everything in moderation» mantra.

The role of stress

It is not covered in the recent study, but part of the concern is the amount of stress during pregnancy, which is very common, according to the dietitian. Erin Kenney , MS, RD.

«In addition to changes in metabolism during pregnancy that keep caffeine in the system longer, caffeine also stimulates the secretion of stress hormones the catecholamines adrenaline and norepinephrine.»says Kenney. «Depending on how much stress the mother is already under, this burden can be overwhelming. When these stress hormones are released, they can increase placental vasoconstriction and increase fetal heart rate, leading to impaired fetal oxygenation.» .

There seems to be a dose-related response, he adds, which means that higher intake leads to a higher risk, so low intake may not be a concern.

Caffeine also stimulates the secretion of the catecholamine stress hormones epinephrine and norepinephrine … When these stress hormones are released, they can increase placental vasoconstriction and increase fetal heart rate, leading to affected fetal oxygenation.


For healthy, unstressed women with a balanced lifestyle, good gut health, adequate hormone levels, and a nutritious diet, Kenney would probably recommend that 200 mg of caffeine a day be generally safe. These are two 8-ounce cups of brewed coffee, depending on factors such as what kind of coffee beans are used and how they are prepared.

However, even then, pregnant women should be aware that slowing down clearance during the second and third trimesters could mean switching to decaffeination.

What does this mean for you?

Pregnant people should keep in mind that this is a preliminary analysis, so no clear recommendations have been made yet. However, there is enough evidence to warrant caution when it comes to caffeine consumption, so it is important to be aware. If you are not willing to completely cut down on caffeine, you may want to consider switching to white or green tea, which has a much lower level of stimulant.