In a candid essay for Lenny Letter this week, Cobie Smulders opened up about the ovarian cancer diagnosis she received when she was only 25 years old: “Just when your ovaries should be brimming with youthful follicles, cancerous cells overtook mine," she writes, "threatening to end my fertility and potentially my life."

Now 34 and a mother of two, the star is hoping to raise awareness about the deadliest form of female reproductive cancer, estimated to affect some 22,000 American women in 2016 alone.

It's rare for the disease to strike a woman in her 20s, but not impossible. There are several forms of ovarian cancer, including hereditary types linked to the BRCA gene mutation. The hereditary types are more likely to occur in younger women, says Nimesh Nagarsheth, MD, associate professor of obstetrics, gynecology, and reproductive science at Icahn School of Medicine at Mount Sinai. “The epithelial ovarian cancers are the more commons ones that we hear and talk about, which generally occur later in life." (Smulders hasn't said what type she had.)

However, Dr. Nagarsheth adds, there are no rules about what types of ovarian cancer will strike when, or how a patient’s age will affect her outcome: “There’s so much more to it than just age,” he says. “There are too many variables—like the type of cancer and its aggressiveness—to make generalized statements about ovarian cancer in younger populations.”

It's safe to say that most 20-somethings don’t have the disease on their mind. As Smulders writes in the beginning of her moving essay, “I was 25. Life was pretty simple.” But when her body began to feel “off,” she didn't ignore her symptoms: “My energy was low, I was just so tired all the time, and I felt a constant pressure on my abdomen that I could not explain. I listened to my body and immediately went to my gynecologist.”

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The fact that Smulders saw her doctor then may have saved her life. When the disease is caught early, 94% of women will survive longer than five years. But in most cases, ovarian cancer isn't diagnosed until stage 3 or 4.

One reason it goes undetected is that there's room in the abdomen and pelvis for organs to shift as the cancer grows, says Dr. Nagarsheth. “You don’t really notice it until you have areas that can no longer move due to the fact that there’s a large mass or tumor within."

Once symptoms do present, patients may experience abdominal pain or discomfort (as Smulders described), as well as bloating, constipation, and early satiety (or a "full" feeling after eating a small amount of food), Dr. Nagarsheth says.

“Every person is different and every situation is different," he adds. "If there are any signs or symptoms you’re experiencing, the best thing to do is talk to your gynecologist or primary care physician. Do not be afraid to get your symptoms checked.”  

Smulders now has a clean bill of health, after enduring multiple surgeries, and trying a long list of lifestyle changes and alternative therapies. She urges other women faced with scary diagnoses to take their health into their own hands: “If you are going through something like this, I urge you to look at all your options. To ask questions. To learn as much as you can about your diagnosis. To breathe. To ask for help. To cry and to fight.”

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If you want to reduce your risk of developing ovarian cancer, you might consider the pill, says Dr. Nagarsheth: “Taking birth control pills for up to two to three years can reduce your risk by up to 40 to 50%.”  Pregnancy is also protective against the disease.

Women who are at particularly high risk may consider prophylactic procedures, he adds. “BRCA mutation patients or hereditary risk patients have more options. They may choose to take out their [fallopian] tubes and ovaries at an early age because they have a known, definitive, genetic risk factor.”