Does Caffeine Affect Your Fertility?

Reviewed by Dr. Elisa Ross in June 2010

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You drink coffee throughout the day, or maybe soda is your pick-me-up of choice, but could your caffeine habit be affecting your fertility?

You wake up, groggy, to the smell of freshly brewed coffee. It takes a couple of cups to get you out the door in the morning. When the food coma hits after lunch, it takes a diet cola (or two!) to get you over the hump. This could describe many of us—but what if you're trying to get pregnant? Does all the caffeine that gets you through the day hurt your chances of conceiving?

If you drink enough of it, the answer is yes, according to Ronald Gray, PhD, a professor in population and family planning at Johns Hopkins Bloomberg School of Public Health. A few years ago, Dr. Gray researched the question of caffeine and fertility. "What we found is that women who consume high amounts of caffeine daily take longer, on average, to get pregnant than women with low or no consumption," he said. "They had nearly three times the risk of not being able to conceive after one year of trying."

How Much Is Too Much?

What exactly constitutes a "high amount?" In Dr. Gray's study, anything over 300 milligrams per day, which is the equivalent to about two 8-ounce cups of drip-brewed coffee, four 8-ounce cups of tea (hot or iced), nine caffeinated sodas, or 15 ounces of dark chocolate.

Other studies from research groups at Yale University School of Medicine and the National Institute of Environmental Health Sciences have confirmed that consuming over 300 milligrams of caffeine per day reduces fertility, but a study from Alicante University in Spain found effects only at levels of 500 milligrams per day or more. The bottom line is that for your best chance of conceiving quickly, it's best to reduce or eliminate caffeine consumption. Remember to count all of your caffeine sources when figuring out how much you need to cut back.

Cutting Back on Caffeine

How can you cut back without too much pain? We asked some women who were able to successfully limit caffeine to share their tricks:

"I was a serious caffeine drinker," says Amy Story of Westford, Massachusetts. "I made a deal with myself. I'd nurse one diet cola all day long by pouring some into a tiny cup. After I drank the tiny bit of cola, I'd have to drink three times that amount of water. Then I gave myself permission to have another tiny cup of cola."

"I switched over to decaf iced tea, slowly decreasing the number of glasses of the real stuff each day," said Sally Haskell of Brentwood, Tennessee. "It was hard at first. I had to be careful to go slowly over many days, otherwise I'd pay for it with a whopping headache."

Mary North of Ann Arbor, Michigan, recalls: "For me the ritual of making coffee in the morning and the smell and taste of that first sip are as important as the caffeine effect. I switched to decaf French roast and did not feel deprived." Decaffeinated coffee and other beverages are not caffeine-free, but only contain about one-tenth the amount of caffeine.