What Research Says About Caffeine During Pregnancy

Two teams of researchers recently weighed in on the safety of ingesting caffeine during pregnancy, and they came to two very different conclusions.

The first study, which appeared in the January 2008 issue of the American Journal of Obstetrics and Gynecology, came from researchers at Kaiser Permanente. They tracked the caffeine intake of more than 1,000 women through early pregnancy. Those who reported drinking more than 200mg of caffeine per day were more than twice as likely to have a miscarriage as those who drank none. And those who drank smaller amounts of caffeine were about 40% more likely to miscarry than those who drank none.

On the other hand, researchers at New York’s Mount Sinai School of Medicine found no link at all between caffeine intake and miscarriage. The study, published in the January 2008 issue of Epidemiology, followed more than 2,400 women, most of whom were light to moderate coffee drinkers.

My take? Caffeine easily passes through the placenta, into the amniotic fluid and umbilical cord blood, and on to the developing baby—who will have higher and more sustained caffeine levels than Mom, because of an immature metabolism. Still, interpreting the above studies proves difficult because caffeine may not be the only factor affecting the results. A woman who avoids caffeine while pregnant is likely to make other healthy choices as well and those decisions could collectively benefit her and her baby more than the caffeine avoidance alone.

I recommend cutting off caffeine at 150mg per day. A growing number of studies suggest that an average caffeine intake of over 150mg a day during pregnancy may indeed increase the risk of miscarriage, preterm labor and low birth weight. But since the research linking pregnancy problems to smaller amounts of caffeine is much less clear, completely cutting it out of your diet might be going overboard.

Whether you keep sipping your daily cup or decide to go cold turkey during pregnancy, this guide to caffeinated foods and drinks should help you determine your potential caffeine intake.

Typical Caffeine Content in Foods


Caffeine (mg)*

Mocha Cappuccino


Coffee, brewed by drip method, 5 oz.


Coffee, instant, 5 oz


Decaffeinated coffee, 5 oz.


Latte, 12 oz.


Brewed teas, 5 oz.


Decaffeinated or herbal teas, 5 oz.


Some dark carbonated beverages, 12 oz.


Citrus flavored carbonated beverages, 12 oz.


Decaffeinated carbonated beverage, 12 oz.


Cocoa beverages, 5 oz.


Chocolate milk, 8 oz.


Milk chocolate, 1 oz.


Chocolate syrup, 2 tablespoons


Semi-sweet chocolate, 1 oz.


Iced tea, 12 oz.


Espresso, 2 oz



Source: Raising Baby Green (Jossey-Boss, 2007). Adapted from FDA Consumer, December 1987/January 1988, and “Facts Help Calm Concerns Brewing over Kids and Caffeine.”

Published on: March 26, 2008
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Dr. Greene is a practicing physician, author, national and international TEDx speaker, and global health advocate. He is a graduate of Princeton University and University of California San Francisco.
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