When it comes to conclusions about the link between caffeine and fertility, it’s a buyer’s market. If you don’t care for the answer you get from one source, find another. You’ll almost certainly get a different one. While there have been studies that have found a link between decreased fertility in women and consumption of large amounts of caffeine, many of those studies did not account for other factors that would reduce fertility, such as smoking or high alcohol consumption. Other studies found no link at all, and at least two concluded that caffeine increased a woman’s fertility, especially at the beginning of an attempt to conceive.
The same holds true for men and their fertility. Some studies found that caffeine increased a man’s sperm count if it was low and decreased it if the count was in the normal to high range. A study in Brazil found the only effect caffeine had on sperm was to make them swim faster, regardless of how many cups of coffee a man drank a day. Another study concluded the exact opposite, that caffeine made sperm sluggish. A third found caffeine increased the sperm’s ability to reach the egg at just the right time for conception to occur.
Why the Confusion?
Much of the problem in finding a clear answer to the question of whether or not caffeine impacts fertility lies in how the various studies on caffeine are conducted. Caffeine can be ingested in many ways, including pure pill form or via coffee and tea. Different delivery methods produce different results. Caffeine in coffee or tea comes with a fairly high dose of antioxidants, which can have beneficial effects of their own. Caffeine in pill form does not. Studies on rats and mice are given as much significance in the media as studies on humans, and humans themselves are notoriously hard to study. Rats can at least be contained. Once a person steps out of the lab, there’s any number of things they can do to throw off a study. There’s caffeine in chocolate bars. There’s a lot of caffeine in Midol. Ingesting either one can throw off the results of an experiment.
What We Do Know
It can be very hard to sort out fact and fiction when it comes to caffeine and fertility. One day caffeine is good for you, and the next day it’s not. But if you sift through the results of the various studies, it’s possible to come up with a couple of conclusions. One is that moderate caffeine consumption, 300 milligrams a day or less, has not been found to have an effect on fertility in men or women. That’s about 2 to 3 cups of coffee, depending on how it’s brewed. Neither does that amount seem to have any effect on the chance of miscarriage, low birth weight or birth defects. Whatever effect caffeine has on fertility, good or bad, it is far outweighed by the effects of a healthy diet, low alcohol consumption and not smoking.