Polycystic ovarian syndrome (PCOS) is becoming a significant problem in women’s health. Between 1 in 10 to 20 women have the condition, although more than 50 percent remain undiagnosed. PCOS is the leading cause of female infertility and women who do become pregnant have higher rates of miscarriage, preterm birth, and gestational diabetes.

Women with PCOS have a greater likelihood of developing diabetes, cardiovascular disease, and endometrial cancer than women without the condition. Glucose intolerance is caused by associated insulin resistance that frequently, but not always, causes weight gain. Although there are diagnostic variances between national societies, PCOS is characterized by androgen excess, ovulatory dysfunction, and polycystic ovaries. Only two out of three criteria are necessary to establish the diagnosis.

However, many women see multiple physicians before they receive a correct diagnosis. I was trained at the Drexel Center for PCOS in Philadelphia, PA and have diagnosed and treated hundreds of PCOS patients. Through this experience, I have seen many different phenotypic presentations of PCOS. Experts publishing PCOS literature agree that these phenotypic differences contribute to the difficulty in making a diagnosis and many even suggest renaming the syndrome.

Here are some reasons you might be missing PCOS:

1. Her periods are regular.  It’s important to clarify what a patient means by “regular.” She may be having prolonged cycles, but regular (35 to 38 days). Many women report very heavy, but regular cycles. It is possible, and common, to have anovulatory cycles even though bleeding occurs at regular intervals. Many PCOS patients ovulate inconsistently, but periodically. Heavy periods are more likely with anovulation since there is inadequate progesterone to balance estrogen.

2. She is not overweight. Abnormal weight gain is common with PCOS, reflecting insulin resistance. But up to 1 in 5 women with PCOS have lean PCOS, that is, they have all of the diagnostic criteria but are under- or normal weight. Clinicians should remain suspicious of the condition in thin women presenting with infertility or irregular cycles. Lean PCOS patients often still have insulin resistance.

3. She doesn’t have ovarian cysts. Since polycystic ovaries are not necessary to make the diagnosis, many specialists believe the syndrome should be renamed (e.g., androgen excess syndrome). Women can also have characteristic small follicular cysts (i.e., “string-of-pearls”) that are asymptomatic and thus are never assessed by pelvic ultrasound.

4. She’s had a baby before. PCOS sometimes worsens with age, so this clinical presentation is typical in a woman who had children in her early 20s and then developed symptoms later in life.

5. She doesn’t have acne or hirsutism. Some women are plagued with clinical signs of androgen excess such as oily skin and hair, acne, male-pattern balding and hirsutism.  However, some women have few of these symptoms even with elevated androgens, demonstrating the phenotypic variability. Testing should include testosterone, DHEA-S, and androstenedione.

6. She has no family history of PCOS. There does seem to be a genetic component with PCOS. However, since the incidence is increasing, potentially due to an environmental component in the form of endocrine disruptors, it’s not unusual for a patient to have no significant family history. It’s also likely that family members may have not known they had the condition or not disclosed it. Family history of glucose intolerance is very commonly associated with PCOS.

7. She never had trouble becoming pregnant. Since ovulatory dysfunction is variable in presentation, there are some women who have no fertility problems but are symptomatic of androgen excess, insulin resistance and other menstrual abnormalities such as heavy periods.

8. She went to doctors for years, and no one mentioned PCOS. Unfortunately, this is the norm for many PCOS patients, especially if they have a milder case of PCOS.  Hopefully, there will be more primary care health care providers who will begin picking up on the diagnosis as more medical information is disseminated. Acne is a common presenting symptom with PCOS.

9. She didn’t start having problems until she got off birth control. This is a common problem if women have been on birth control for prolonged periods of time and especially if they were started on birth control for abnormal cycles. Most women will revert to whatever their underlying hormonal issue was when they go off birth control.

10. Other than unexplained weight gain, especially belly fat, and sweet/carbohydrate cravings, she doesn’t have any other symptoms of PCOS. Insulin resistance is often the presenting symptom of PCOS, so a careful history is in order. The 2-hour glucose tolerance test is commonly substituted with a Hemoglobin A1C and an insulin level. Hormonal testing should be considered in patients who have abnormal glucose metabolism and menstrual symptoms, or who have darkened skin around their neck, axilla or groin (acanthosis nigricans).

Poppy Daniels is an obstetrician-gynecologist, Family Birth & Wellness Center, Springfield, MO.  She can be reached @drpoppyBHRT on Twitter.