One of my earliest memories of coffee was a warning from my mom not to drink it. “It will stunt your growth,” she said. Somewhere along my path to adulthood, however, I discovered Starbucks (and Stumptown and Coffee People and Peet’s and countless quirky independent coffee shops). Now, I love the stuff. Many of my patients feel the same way, but that warning from our mothers has stuck in the back of our minds, especially when it comes to pregnancy. I get asked about the safety of caffeine quite often.

Almost 90% of women of child-bearing age in the United States consume caffeine. Usually, this comes in the form of caffeinated drinks like coffee, tea, and soda. It also is consumed in foods like chocolate. Here are the levels of caffeine in the some of the most common sources:

 Eight-ounce cup of coffee 75 – 250 mg
 Can of Coke 46 mg
 Typical cup of tea 35 mg
 Serving of chocolate brownies 10 mg

Caffeine is a drug that is rapidly absorbed by the human body and it readily transported to most tissues, including crossing the placenta to the developing fetus. But is it harmful? Let’s break this question down a little and hopefully it well help provide some clarity.

Does Caffeine Cause Infertility?

The scientific studies are a little confusing on this issue. Some of them show a negative effect, but the better studies show no harm with moderate consumption. Probably, a small amount of caffeine (e.g. one eight-ounce cup of coffee per day) is safe. For couples needing in vitro fertilization to conceive, there may be some correlation between caffeine consumption and decreased number of eggs retrieved. For these couples, it is probably best to avoid caffeine.

Will Caffeine Cause a Miscarriage?

A recent study reviewing all of the science around caffeine showed that even very high doses of caffeine don’t seem to increase the risk of miscarriage. This doesn’t mean it is OK to consume caffeine excessively, but moderate consumption is OK. The equivalent of one cup of coffee per day is fine.

Will Caffeine Cause Problems for My Baby?

Moderate consumption of caffeine during pregnancy does not appear to cause birth defects, preterm labor, still birth, poor fetal growth or health problems for babies after they are born. Excessive caffeine consumption (greater than 200 mg per day) may decrease fetal growth a small amount. Again, one cup of coffee per day is safe.

What About Breastfeeding?

Caffeine crosses into breast milk in small amounts. Babies receive a dose of about 1% of what the mother is getting. Moderate consumption (less than 200 mg per day) is safe with breastfeeding. Consuming large amounts of caffeine will increase the amount of caffeine the baby gets, which might increase irritability and interrupt sleep.

In Summary

When consuming caffeinated foods and drinks, it is important to use moderation. Most of the high quality scientific evidence suggests that moderate consumption of caffeine is safe before, during and after pregnancy. I tell my patients it is OK to consume caffeine, but I recommend they consume less than 200 mg per day, which is about equivalent to an eight ounce cup of strong coffee.

Have you just found out you’re pregnant? Women’s Healthcare Associates has OB/GYN physicians and certified nurse midwives who deliver babies at six hospitals in the Portland metro area. Contact one of our offices to schedule an appointment >