Does Coffee Really Affect Your Fertility?

Nicole Van Groningen, MD is an Internal Medicine physician at the University of California, San Francisco.

As a physician, patients often ask my opinion on their coffee intake, anxiously expecting me to, like many of the internet's popular health advisors, advise them to cut it out altogether. By and large, they're relieved by my resounding support for their coffee habits. After all, coffee drinking, in low to moderate levels, is associated with improved mental functioning, lower risk of heart attack and diabetes, improved athletic performance, and even decreased risk of death from all causes.

But for women in their 20s and 30s, a new, and often more pressing, question often arises: does coffee — and the caffeine it entails — affect reproductive health?

The short answer, to the relief of my coffee-loving patients, is probably not — with one caveat.

When it comes to fertility, high-quality studies have shown that there is zero significant difference in fertility between coffee drinkers and non-coffee drinkers. In other words, your coffee habit won't limit your ability to conceive (alcohol and smoking, on the other hand, assuredly will). There's even an advantage to drinking coffee while you're trying to get pregnant: in one study, women who drank coffee prior to conceiving actually had a decreased risk of gestational diabetes.

But once you become pregnant, does caffeine affect the baby-to-be? Although caffeine does cross the placenta, where it causes subtle physiologic changes in the growing baby, the body of medical evidence suggests that these effects aren't harmful. Specifically, there's no high-quality data to suggest that drinking coffee during pregnancy leads to any increased risk congenital malformations, pre-term delivery, or low birthweight.

Coffee has been associated, however, with miscarriage — but only when caffeine intake exceeds 300 mg, or around 3 cups of coffee a day. For reference, women of reproductive age consume an average of 164 mg per day, so unless you're guzzling Starbucks multiple times a day, you're probably in the clear.

My professional take (and — full disclosure — that of a self-proclaimed coffee addict) is that there's no need to cut out your morning latte if you're pregnant or trying to become pregnant. Just make sure to take it easy, and limit coffee intake to 1 or 2 8 oz cups per day. This equates to, at most, 200 mg of caffeine daily, a limit generally accepted as safe by the March of Dimes, the American College of Obstetricians and Gynecologists, and the American Dietetic Association.