Trying to conceive? You may want to put down that Mountain Dew.

Infertility is unfortunately common in the United States. According to the CDC's National Survey of Family Growth, 12.1 percent of women between the ages of 15-41 have impaired fecundity—meaning it’s difficult or impossible for them to become pregnant.

There are many factors at play when it comes to fertility, but a recent study, published in Epidemiology found links between drinking one or more full-sugar sodas a day and a decreased chance of getting pregnant.

Americans are eating more sugar than they have in decades—a large portion of which comes from sugary drinks. Drinking sugar-sweetened beverages has already been linked to weight gain and type 2 diabetes.

But researchers from the Boston University School of Public Health wanted to see if there was also a connection between the increase in sugar, and a decrease in fertility. So they surveyed 3,828 women—ages 21 to 45—and 1,045 of their male partners.

Participants took a diet and lifestyle survey, and female participants completed a follow-up questionnaire every two months for up to a year (or until they got pregnant).

“We found positive associations between intake of sugar-sweetened beverages and lower fertility, which were consistent [even] after controlling for many other factors, including obesity, caffeine intake, alcohol, smoking, and overall diet quality,” wrote Elizabeth Hatch, professor of epidemiology and lead author of the study in a press release.

The study found that drinking one sugar-sweetened beverage a day—by either partner—was associated with an overall 20 percent reduction in fecundity. And women who drank more than one soda a day had 25 percent lower fecundity, while their male partners had 33 percent lower fecundity.

Energy drinks were related to even larger reductions in fertility, but results were based on a smaller sample size, so more research will need to be done to draw a clear link.

The bottom line: Drinking the occasional Dr. Pepper or Red Bull may not seem like a huge deal, but if you’re struggling to conceive you may want to lay off the sugary drinks. Dr. Hatch said in a press release, “Couples planning a pregnancy might consider limiting their consumption of these beverages, especially because they are also related to other adverse health effects.”