Watch the caffeine if you're pregnant

Consumer Reports News: November 20, 2008 02:16 PM

Whether it's a short, bitter shot of espresso or a comforting, milky latte, there's no denying that, when most people think of caffeine, they think of coffee. But it turns out that women who are pregnant or thinking of having a baby may be better off cutting back on coffee, along with other foods and drinks that contain caffeine.

In a new study, researchers looked at more than 2,000 pregnant women in Britain. They found that women who were getting more than 200 milligrams (mg) of caffeine a day (equivalent to two small cups of coffee) were more likely to give birth to an underweight baby.

Some doctors already advise women to go easy on the coffee while pregnant. But in this study, most of the caffeine women consumed came from other sources. About 62 percent was from tea, with 14 percent coming from coffee, and 12 percent from cola. Chocolate accounted for 8 percent of women's caffeine intake, with smaller amounts coming from hot chocolate and energy drinks.

The British are famously fond of tea, so American women's diets are likely to be different. Even so, the results show that keeping a lid on your caffeine intake means being careful about more than just coffee. It's made more difficult by the fact that not all products that contain caffeine will say so on the label.

The charity March of Dimes recommends that pregnant women consume no more than 200 milligrams (mg) of caffeine per day, which is the same safe upper limit that the study found. Here's the amount of caffeine you can expect to find in some common foods and drinks:

  • 100 mg in a small (6-ounce) cup of coffee. Watch out for much larger servings in coffee shops
  • 50 mg in a cup of tea
  • Around 34 mg in a 12-ounce can of cola
  • Around 50 mg in a 2-ounce bar of plain chocolate (milk chocolate contains about half as much).

Energy drinks are often very high in caffeine, with the exact amount depending on the brand and serving size. Some medications also contain caffeine. Check the pack or talk to your pharmacist if you're not sure about any drugs you're taking.

Although the study found that women who got lots of caffeine had smaller babies on average, the difference was small. Babies whose mothers had more than 200 mg of caffeine a day weighed two or three ounces less, on average. But the researchers say this could make a difference to a baby's health if they were already at risk for other reasons.

What you need to know. There's no need to cut out caffeine completely if you're pregnant, but the more you have, the bigger the risk of an underweight baby. Aim to stick below the recommended maximum of 200 mg of caffeine a day.

—Philip Wilson, patient editor, BMJ Group has partnered with The BMJ Group to monitor the latest medical research and assess the evidence to help you decide which news you should use.

Read more on the 10 over-the-counter drugs pregnant women should avoid—including drugs that contain caffeine, and learn about coffee perks and concerns.

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