Eight years ago, when she was just 16, Ashley Nicole Ingram was in her ob-gyn's waiting room flipping through an issue of Glamour when she saw a story about polycystic ovarian syndrome (PCOS). "I realized that that might be the reason I was having such erratic periods," recalls Ingram, now a political campaign manager in Los Angeles. "I ripped it out and showed it to my doctor, but he told me it was normal for young women to be irregular. I saw a number of doctors in my teens, and they all said the same thing." But when Ingram was 18, her hair started falling out; then she gained a whopping 60 pounds. So she made an appointment with a reproductive endocrinologist, a type of doctor specializing in hormonal issues, who ran a blood test and told Ingram what she'd already known in her gut: She had PCOS. Not only that, but she was also showing signs of early diabetes, a complication of the condition. It had taken her nearly a decade to be diagnosed—and believe it or not, that makes her one of the lucky ones. Many women with PCOS suffer year after year before their illness is correctly diagnosed. The story is just as dismal for endometriosis, a painful condition that, like PCOS, affects as many as 10 percent of young women, takes seven years on average to be diagnosed and is a leading cause of infertility. "I had symptoms even as a teenager—heavy, clotty periods with diarrhea," says Kristina Grish, 34, a writer in New York City, who was diagnosed with endo three years ago. "The pain was so bad I'd curl up in a fetal position for a day, and go through super tampons in an hour. Yet every gyno I saw told me it was normal."

If a woman can diagnose her own symptoms after reading a magazine article, how on earth can doctors miss these illnesses? "As someone who sees women with both diseases every day, I find it strange and alarming that this still occurs," says Roger Lobo, M.D., professor of obstetrics and gynecology at Columbia University Medical Center in New York City. Glamour went to top experts to find out why these conditions are overlooked and what to do if you suspect you have one.

The Truth About PCOS

PCOS is, in essence, a hormonal imbalance in which excess "male" hormones like testosterone disrupt ovulation and wreak havoc on a woman's body. The first signs of PCOS, like acne and irregular periods, often show up in the teen years, when it's all too easy to attribute them to the hormonal changes all adolescents go through. Doctors may try to "treat" these symptoms with oral contraceptives, and "what happens is that women don't realize their periods are still irregular until they go off the Pill 10 or 15 years later to get pregnant, and then they can't conceive," says Rhoda H. Cobin, M.D., an endocrinologist at the Mount Sinai School of Medicine in New York City. Weight gain is another symptom, but it's such a common complaint among even healthy women that some doctors may get jaded about patients' concerns. "They assume a patient is blaming her weight gain on hormones, rather than admitting to being inactive or eating poorly," says Andrea Dunaif, M.D., chief of the division of endocrinology at Northwestern University Feinberg School of Medicine in Chicago.

Adding to the confusion? You don't have to have every symptom to have the disorder. "If a woman has irregular periods but isn't overweight, for example, a doctor may assume she doesn't have PCOS," says Dr. Lobo. Around 30 percent of women with the condition are not overweight, he says. Some of the responsibility lies with women, too. We may not tell our ob-gyns about symptoms that seem simply cosmetic, like hair loss or skin tags (molelike flaps of tissue). The lesson: Share as many details with your doctor as you can, and if you feel you're being ignored, see someone else or get a referral to a reproductive endocrinologist.