Earlier this summer, retired U.S. soccer player Lauren Holiday was sailing through her first pregnancy when suddenly, she began experiencing painful headaches. An MRI revealed a tumor on the right side of the 28-year-old's brain near her orbital socket, the Times-Picayune reports

Fortunately, the two-time Olympic gold medalist's growth is benign, operable, and not a risk to Holiday's unborn daughter. She's scheduled to have the tumor removed about six weeks after her delivery.

Though Holiday has a positive prognosis, her story is still scary because she's young and otherwise healthy—elite-athlete-level healthy. But next time you get a piercing headache, don't jump to any conclusions. The ones brought on by brain tumors aren't your average headaches, says John G. Golfinos, MD, chair of the department of neurosurgery and co-director of the Brain Tumor Center at NYU Langone Medical Center. They're persistent, and tend to be worse in the morning and improve throughout the day. “That’s because when people are lying flat, the pressure in the skull and brain goes up, and during the day some of the pressure starts to go away,” he explains. What's more, brain tumor headaches are often associated with nausea and vomiting.

More good news: brain tumors are pretty rare. You have just a 1% chance of developing a malignant brain tumor in your lifetime, according to the American Cancer Society. 

Here, Dr. Golfinos reveals more facts to know about brain tumors: 

Not all brain tumors are cancerous

“There’s a whole spectrum and range of outcomes for brain tumors,” says Dr. Golfinos. As in Holiday’s case, some are benign, “which means they grow very slowly in the brain or just outside the brain,” he explains. Others are malignant, grow very quickly, and are incurable.

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Even benign tumors can cause major issues

The reason brain tumors can be so risky is that the skull is a thick, confined space: “So anything that grows inside or just outside the brain can take up a lot of room and press on important parts of the brain, causing a lot of problems,” he says. “That’s why we say with brain tumors, it’s not just what type of tumor is it, but where is it.”

The problems can include loss of vision, difficulties with speech, issues understanding language, or weakness on one side of the body. Symptoms can be subtle in the beginning, especially if they're caused by a benign, slow-growing tumor, says Dr. Golfinos. But if you notice any of those changes, it’s a good idea to see your doctor.

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Brain tumors can’t escape your skull

Brain tumors are unique in that they can't spread to other organs, since they don't have the same access to the blood stream that tumors in other parts of the body do, says Dr. Golfinos. “The brain itself is a very privileged part of the body,” he notes. “It's good at keeping things out, but also good at keeping things in.”

Your phone won’t cause a tumor

You may have heard the myth that constantly talking on your cell causes cancer. According to Dr. Golfinos, you have nothing to worry about, since there's no good evidence to suggest this is true. The reality, he says, is that “[w]e really don’t understand what causes brain tumors.”

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You can't prevent tumors from developing

“Many people ask me if there’s anything they can do to avoid brain tumors,” says Dr. Golfinos. “And right now the answer to that is ‘no.’” That said, to play it safe, Dr. Golfinos recommends avoiding exposure to excess radiation whenever possible (by opting for an MRI over a CT scan for example), especially for anyone under the age of 18.