PCOS affects between 5-10% of reproductive age women, making it the most common hormonal disorder. (Bozdag G, et al. 2016) And as you may know, it can really throw a wrench in your fertility plans. I get tons of questions about PCOS and why it seems to be experienced so differently. Keep in mind as you read this that PCOS is called a SYNDROME, instead of a disease, frankly, because it is so variable in the way each woman expresses it and by the myriad of factors that characterize it.
Originally named Stein-Leventhal Syndrome in 1935 and used to describe women with irregular menses, coarse, male-pattern hair growth on their faces, and enlarged ovaries with multiple cysts. Since 1935, PCOS diagnosis has expanded to include women outside of the typical pattern initially described, and now there are Four Different Types of PCOS! Technically, they are called phenotypes, which is just a fancy way of saying that the same syndrome can physically show up differently. Interestingly, there is a movement to change the name because many women don’t have ‘cystic’ ovaries but still have PCOS. WHAT?!? I know, it’s complex and can be quite confusing.
There have been a few different iterations of the diagnostic criteria over the years.
1990: NIH (National Institutes of Health) Criteria
- Delayed ovulation or periods (oligoovulation, oligomenorrhea)
- Excess androgens (testosterone, DHEAs, androstenedione) leading to acne, hirsutism (male-pattern hair growth in women), male-pattern hair loss
- Cystic ovaries visualized on ultrasound
- Other conditions with similar signs and symptoms excluded
2003: Rotterdam Criteria (ONLY 2 of the 3 criteria are required for diagnosis.)
- Irregular ovulation or menstrual cycles (oligoovulation, oligomenorrhea)
- Lack of ovulation (anovulation)
- Fewer than 10 menstrual cycles in one year (oligomenorrhea)
- Menstrual cycles longer than 35 days
- Hyperandrogenism
- Acne, hirsutism (hair growth (usually dark & coarse) on the face (upper lip & chin), chest, between the belly button and pubic hair), Male pattern hair loss) AND/OR
- High levels of the androgens testosterone, DHEA, or androstenedione on bloodwork
- Polycystic ovaries (which are not even true cysts, they are follicles) on ultrasound OR Increased ovarian volume
- 12 or more follicles measuring 2-9 mm on a single ovary
- Note: This criterion is still used, but the validity has come into question because 50% of normal-cycling women met the threshold of 12 or more follicles in each ovary in a 2010 study (Johnstone EB, et al. 2010)
- A new criterion was proposed in 2014; 25 or more follicles measuring 2-9 mm on a single ovary using new ultrasound technology (>8 MHz). However, this technology is not readily available to most clinicians. (Dewailly D, et al. 2014)
- In 2018, a threshold of 20 or more follicles in a single ovary was recommended but was never added to the Rotterdam criteria. (Teede HJ, et al. 2018)
- 12 or more follicles measuring 2-9 mm on a single ovary
OR
- Ovarian volume >10 mL in a single ovary
- Note: Ultrasounds are best done on cycle day 3 (CD3), but can be done on any day of the cycle
- Ovarian volume and follicle number naturally decrease with age in women with or without PCOS. Age-based criteria to define polycystic ovaries have therefore been proposed. (Alsamarai S, et al. 2009)
When the Rotterdam Criteria were published, it created some controversy, but included more women in the PCOS diagnosis, because it only required 2 of the 3 criteria. This is what lead to four different types, or more specifically phenotypes, of PCOS.
Four Different Types (Phenotypes) of PCOS
(Norman RJ, et al. 2007)
PCOS Type A : Classic Severe PCOS
- Delayed ovulation or anovulation, irregular periods
- Hyperandrogenic: hirsutism, acne, hair loss, high androgens
- Polycystic ovaries on ultrasound
This is the most classic description of PCOS and also the most severe type, accounting for ~60% of cases. Women included in Type A typically carry more weight, especially around the waist area. Type A does not exclude lean women but is less typical. There is an increased likelihood of insulin resistance, and risk of developing diabetes and heart disease.
Menstrual irregularity in Type A is more pronounced, often with breakthrough bleeding and exceptionally heavy, painful periods with a lot of clots.
Hormonal changes often include the highest testosterone levels of all types, very low progesterone with high relative estrogen, high AMH (anti-mullerian hormone which has been used as a surrogate marker for ovarian reserve but is elevated in PCOS due to the high number of immature follicles), and high LH/FSH ratios on CD3 (controversial).
Type B: Classic, Similar to Type A but Without Cystic Ovaries
- Delayed ovulation or anovulation, irregular periods
- Hyperandrogenic: hirsutism, acne, hair loss, high androgens
- NORMAL ovaries on ultrasound
Type B is not as common as Type A, at 8.4% of women with PCOS, but is more common in older women. There is a tendency for weight gain, although lean women may have Type B, and it still carries an increased risk for diabetes and heart disease. AMH is usually lower than it is in Type A.
Type C: Non-Classic, Ovulatory PCOS
- Regularly spaced periods of bleeding with or without ovulation
- Hyperandrogenic: hirsutism, acne, hair loss, high androgens
- Polycystic ovaries on ultrasound
Women with Type C tend toward a more average weight and waist circumference, with lower LH/FSH ratios (but still slightly elevated compared to a woman without PCOS) than Types A or B. Although androgen levels may be higher than women without PCOS, they are not going to be as high as women with Type A. Interestingly, when women with Type A lose weight or improve insulin resistance there is a tendency to move to to the Type C classification, with more regular periods.
It is important to note that in some instances the fairly regular periods of bleeding that are seen in Type C may be breakthrough bleeding, not a sign of ovulation, which can be misleading.
Type D: Mild PCOS
- Delayed ovulation or anovulation, irregular periods
- No hyperandrogenic signs and relatively normal androgen levels
- Polycystic ovaries on ultrasound
Finally, this is the most controversial type of PCOS, ~16% of cases. Until the Rotterdam Criteria, women with this type were NOT considered to have PCOS at all and many experts still argue that it is not true PCOS. Women with Type D are most likely to be of normal weight (BMI), average waist circumference, and generally do not have or are only mildly insulin resistant. The LH/FSH ratio will likely still be elevated which is why ovulation doesn’t happen regularly and although androgens are relatively normal, they will likely be on the high end of normal or only very mildly out of range. Often women with very mild PCOS fit this category, particularly after stopping birth control.
The reason I even discuss the different types is because I want women to understand that PCOS can look and act differently depending on the individual and often women go undiagnosed and more importantly untreated because of these complexities.
Ultimately, Type doesn’t matter because PCOS is not a static disorder. Depending on where you are in life will determine how you are affected and therapy must be individualized based on your unique PCOS characteristics. PCOS is lifelong so even if you experience improvement, don’t forgo the nutrition and lifestyle changes you’ve made. We are metabolically programmed and unfortunately, the symptoms of PCOS will often worsen as we shift to less healthy lifestyles.
PCOS | Other Diagnostic Considerations
Lastly, even though PCOS is quite common, it is important to note there are many disorders that mimic PCOS and may need to be ruled out based on a full clinical assessment. Here are a few of the most common conditions to consider:
- Cushing’s Syndrome
- High Prolactin Levels (Hyperprolactinemia)
- Hypothalamic amenorrhea
- Hypothyroidism or Hyperthyroidism
- Non-classical congenital adrenal hyperplasia (a rare genetic condition of the adrenal glands)
- Ovarian or adrenal androgen-secreting tumor
- Ovarian hyperthecosis
More On PCOS…
If you found this information helpful, check back for additional blog posts dedicated to PCOS in the coming weeks!
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REFERENCES
- Alsamarai S, et al. Criteria for polycystic ovarian morphology in polycystic ovary syndrome as a function of age. J Clin Endocrinol Metab. 2009;94(12):4961.
- Bozdag G, et al. The prevalence and phenotypic features of polycystic ovary syndrome: a systematic review and meta-analysis. Hum Reprod. 2016 Dec;31(12):2841-2855.
- Dewailly D, et al. Definition and significance of polycystic ovarian morphology: a task force report from the Androgen Excess and Polycystic Ovary Syndrome Society. Hum Reprod Update. 2014 May;20(3):334-52.
- Johnstone EB, et al. The polycystic post-Rotterdam: a common, age-dependent finding in ovulatory women without metabolic significance. J Clin Endocrinol Metab. 2010 Nov;95(11):4965-72.
- Norman RJ, et al. Polycystic Ovarian Syndrome. Lancet 2007;370:685-97.
- Teede HJ, et al. Recommendations from the international evidence-based guideline for the assessment and management of polycystic ovary syndrome. Fertil Steril. 2018 110:364.
