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According to a new review of studies on the safety of caffeine during pregnancy, if you are pregnant or trying to get pregnant, step away from the coffee maker. The new review, published in the journal BMJ Evidence Based Medicine, concludes that no level of caffeine is safe during pregnancy and the current recommendation of limiting caffeine to about two cups of coffee per day needs a “radical revision.”
Up until now, authorities including the American College of Obstetricians and Gynecologists (ACOG) and the Dietary Guidelines for Americans has been advising that pregnant women limit caffeine to 200 milligrams per day (about 2 cups of moderate-strength coffee). That would include 200 mg of caffeine in other beverages like tea or soda.
The New Review
Researchers from Reykjavik University in Iceland looked at 37 observational studies done in the past 20 years on caffeine during pregnancy. Of these studies 32 found that caffeine at any level significantly increased adverse pregnancy outcomes while 10 studies found no or inconsistent evidence. Researchers also looked at previously published reviews of studies on caffeine and pregnancy. Fourteen out of 17 reported increased risk. Of all the studies reporting adverse outcomes there was a small but significant increase in risks for:
- Low birth weight babies
- Small for gestational age babies
- Childhood leukemia
- Childhood overweight and obesity
The researchers caution that these are observational studies, so they don’t establish a direct cause and effect relationship. The studies rely on women recalling how much caffeine they consumed during pregnancy. There may have been other causes like smoking or drinking alcohol that contributed to adverse pregnancy outcomes. However, after reviewing the evidence the researchers conclude that there is substantial and accumulating evidence of a link between maternal consumption of caffeine at any level and increased risks for several adverse pregnancy outcomes.
ACOG’s Position on Caffeine
In 2010, the ACOG Committee on Obstetric Practice issued their opinion on caffeine during pregnancy. They said that moderate caffeine consumption (less than 200 mg per day) was probably safe during pregnancy. However, they cautioned that a final conclusion could not be made and that their recommendation was subject to change pending emerging research. That position reaffirmed in 2020, before the new review came out in BMJ Evidence Based Medicine.
What is certain is that caffeine is a stimulant drug that crosses the placenta, so when a mother’s caffeine level goes up so does her developing baby’s. Caffeine is the most widely used psychoactive substance in history. Psychoactive means that it changes the way your brain functions. Studies in young children show that just 100 mg of caffeine per day can cause heart arrhythmias, high blood pressure, and anxiety. The American Academy of Pediatrics recommends no caffeine for children under age 12.
For now, the standing recommendation is to limit caffeine to 200 mg per day during pregnancy. That may change. If young children should not be exposed to any caffeine, is it really safe to expose your developing baby to 200 mg of caffeine? That’s a good question to ask your OB doctor.