What are the 4 types of PCOS?

The confusing thing about the 4 types of PCOS is that online sources cannot agree on what they type. Some list 4 root causes and some speak of 4 symptom combinations or even 4 stages of PCOS. Let's make sense of it!

In a nutshell

• 4 types of PCOS and symptoms classification based on Rotterdam criteria.
• 4 PCOS phenotypes include 
  
  • oligo/amenorrhea + hyperandrogenism + polycystic ovary morphology (PCOM),
  • and oligo/amenorrhea + hyperandrogenism 'classic PCOS' symptom combinations,
  • hyperandrogenism + PCOM 'ovulatory PCOS,' 
  • and oligo/amenorrhea + PCOM 'non-hyperandrogenic' PCOS.
• 4 common PCOS causes are intrinsic hyperandrogenism, insulin resistance, higher BMI and inherited factors.
• The complex condition of polycystic ovarian syndrome does not evolve in the same stages in different people. However, some age-related parallels exist with more hyperandrogenism concerning younger patients, fertility issues being among the main concerns in 26–35, and insulin resistance concerning patients since the age of 26.

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What approaches to PCOS types exist?

With PCOS, a condition so diverse and growingly surprising as it gets studied, each case requires a thorough examination. It is still reasonable to observe patterns and benefit from similar experiences.

But similar in what sense? The scientific literature usually discusses PCOS phenotypes or, in other words, its manifestation patterns. The condition is notorious for the variety of its symptoms; however, they do not necessarily hit all at once and rather come in typical combinations.

In turn, medical practitioners group the cases by etiology, i.e., the condition's causes. Addressing the root cause can be more effective than using a one-size-fits-all treatment.

Finally, there is a quest to define PCOS stages that warrant similarities in diagnosis, treatment and lifestyle approach across types.

4 types of PCOS and symptoms — what is the link?

Did you know the whole '4 types of PCOS' thing originated from the symptoms classification? The topic became so popular that medical blogs later decided to spin information about other aspects in the same familiar 4-type form. The scientific literature does not stick to four when covering PCOS causes or stages.

On the other hand, the phenotypes come in four for a reason. Here is the story. In 2003, PCOS experts gathered in Rotterdam to discuss diagnostic applications of their evolving knowledge. They agreed on the new approach which is now recognized as 'Rotterdam criteria' and, with some improvements, remains the golden standard to date.

Immediately after these criteria appeared, Ricardo Azziz and other researchers noticed they imply the existence of 4 symptom combinations, exactly, — more than by earlier beliefs. It reminds us that classifications can be arbitrary: they represent the state of research and discourse as much as the condition itself.

Back to the PCOS phenotypes! The Rotterdam criteria state that to confirm the condition, at least two should be present: irregular or infrequent periods, hyperandrogenism, and polycystic ovary morphology. So, here are the 4 types of PCOS and symptoms defining them:

1. Type A: Irregular or infrequent periods + hyperandrogenism (HA) + polycystic ovary morphology

People with type A PCOS simultaneously have irregular or absent periods, high androgen levels, and polycystic ovary morphology. In combination, all three condition hallmarks increase the risks of other adverse symptoms, such as insulin resistance or metabolic syndrome, and make them more pronounced. People with this PCOS type also tend to have the highest weight.

Type A is considered 'classic PCOS' and constitutes nearly half of all registered PCOS cases. However, it does not necessarily represent its prevalence in the general population and more likely means that people with more severe symptoms get diagnosed more often.

2. Type B: Irregular or infrequent periods + hyperandrogenism

Just as A, this phenotype is considered 'classic' PCOS and manifests in similar symptoms and their severity. The key difference is that with phenotype B, polycystic ovary morphology is not detected on ultrasound. 

3. Type C: Hyperandrogenism + polycystic ovary morphology

Type C's nickname is 'ovulatory PCOS' because, despite elevated androgen levels and polycystic ovary morphology, it does not disturb the menstrual cycle much. PCOS features are moderately pronounced. Lean people with PCOS most probably have type C, and in almost 2/3 of all ovulatory PCOS cases, people have normal or lower BMI.

4. Type D: Irregular or infrequent periods + polycystic ovary morphology

Finally, type D symptoms include oligo- or anovulation and polycystic ovaries but not hyperandrogenism. The HA's visible symptoms, such as acne, male pattern hair growth or hair loss, may not bother patients with this 'non-hyperandrogenic' PCOS. Type D is the least pressuring on the metabolic system and bears the lowest risks of adverse comorbidities.

What are the 4 types of PCOS by causes?

While testing for PCOS symptoms gives definite answers and 'types,' discovering its causes is much more complex. In fact, the exact triggers of the condition are still an enigma to the scientists. However, there is a list of the most probable 'suspects' associated with PCOS fast-track development. The respective 4 PCOS types are:

1. Intrinsic hyperandrogenism PCOS

The majority of registered PCOS cases are associated with increased androgen production. Besides counting as one of the diagnostic criteria itself, hyperandrogenism inhibits ovarian function and can promote PCOM and menstrual abnormalities.

Excess 'male hormones' can come from ovaries or adrenal glands, with adrenal PCOS being a known subtype. Moreover, as adipose tissue converts weaker androgen dehydroepiandrosterone (DHEA) into more potent ones, its excess can also contribute to heightened levels of androgens. 

Hyperandrogenism is a highly heritable PCOS feature, yet for many people, genetics is not accountable. Insulin resistance and stress are two other major drivers for adrenal dysfunction that may eventually result in PCOS.

2. Insulin resistance PCOS

Insulin resistance (IR) is one of the two major contributors to PCOS development. Insulin is a hormone that regulates blood glucose levels and otherwise engages in metabolism. When body cells become 'resistant' to insulin and do not respond as they should, it causes a domino effect in many other processes. 

Namely, with IR, the hepatic sex hormone binding globulin (SHBG) levels drop while the luteinizing hormone (LH) stimulation exacerbates. That causes excess testosterone production and leads to hyperandrogenism. It may also promote polycystic ovarian morphology and irregular or infrequent periods — PCOS bingo. 

3. Obesity PCOS

Higher BMI is often blamed as the chief cause of PCOS, and most treatment strategies include recommendations on weight management. Recent research demonstrates that weight plays different roles in PCOS development depending on ethnicity and other factors and that 'lean PCOS' cases can be overlooked because of existing prejudice.

However, a statistical study on more than 73 thousand women primarily of European descent has demonstrated a significant association between genetically predicted BMI and risk of PCOS. Higher weight still plays against a large population in terms of PCOS risks. Moreover, it is known to exacerbate other risk factors.

4. Inherited PCOS

As we have already mentioned, certain PCOS risk factors, such as hyperandrogenism and higher BMI, can be inherited. This list is not exhaustive — 20 different gene loci have been identified as PCOS susceptible.

Epigenetics, or the genes' behavior under certain conditions, can also increase the chances of PCOS. The condition may cause a series of adverse cardiometabolic effects in pregnancy and consequently affect fetal development. Despite genetic risks, children of PCOS patients may get some of their genes programmed PCOS-susceptibly in the womb.

What are the 4 stages of PCOS?

We have to say it: with current knowledge, 4 stages of PCOS are not a thing. There is a temptation to classify PCOS, much as many other conditions, into typical boxes from pre-condition to acute symptoms or long-term management against recurrence. However, it is simply not how PCOS works.

This multi-faceted condition challenges researchers with many open questions about its causes, their dark synergy, and differences across populations. 

PCOS can manifest milder in some or most of its features depending on its phenotype — as the case is with type D. Not only does it not bear acne, hirsutism, and other hyperandrogenism signs, it also poses lower risks and lower potential severity of metabolic symptoms. It is still a fully developed form of the condition and warrants respective treatment.

Moreover, sometimes vice versa is true, and the most acute PCOS symptoms do not signify its presence. That happens in adolescents or people who stop using birth control pills — they may struggle with irregular or absent periods and abnormal health growth. The symptoms disappear with natural hormonal changes — and it is recommended against diagnosing the condition in these cases.

It is worth mentioning that symptoms often change with age. One reason is the decreasing androgen production in both ovaries and adrenal glands, which softens hirsutism and acne. Another change naturally happens in the ovaries which have fewer follicles with time. 

Metabolic features and comorbidities and reproductive issues, on the contrary, can become a growing concern with age. As a cross-country study on nearly 1400 people defined, IR is among the key concerns for 26–35- and over 45-year-old patients with PCOS, and reproductive concerns preoccupying mainly patients aged 26 to 35.

What is true about managing PCOS stages is that the condition requires a holistic approach regardless of how long it is present. That includes treatment against physical symptoms, lifestyle management and mental health management.

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