Introduction | Understanding PCOS

Understanding PCOS

Chapter 1

Introduction

An introduction to polycystic ovary syndrome (PCOS), the most common hormonal disorder among women of reproductive age and a leading cause of infertility. The chapter sets out how the World Health Organisation and the widely used Rotterdam Criteria define the condition, traces its history back to Stein and Leventhal's first description in 1935, and looks at how common it is, from around 6 to 13% of women worldwide to regional estimates for China and Southeast Asia. It also explains why so many cases go undiagnosed: PCOS rarely causes pain, and its signs, such as irregular periods, acne or weight gain, are easily mistaken for other problems.

In Progress

Chapter 2

Rotterdam Criteria & PCOS Classification

How doctors decide whether someone has PCOS, and why it shows up so differently from one woman to the next. The chapter walks through the history of the diagnostic criteria and the Rotterdam Criteria, under which PCOS is diagnosed when two of three features are present: irregular periods, raised male hormones and polycystic ovaries on ultrasound. It then explains the four Rotterdam phenotypes, how their spread differs between countries, and the two newer subtypes, reproductive and metabolic, including which populations in Asia and Singapore each is more common in and what that means for fertility.

Not Started

lock

Chapter 3

Symptoms of PCOS

A practical guide to the signs of PCOS, which usually appear between the ages of 20 and 30 but can start earlier. The chapter covers ovulation problems, from irregular cycles to periods stopping altogether, and the visible effects of high androgen levels: excess hair growth (and the Ferriman-Gallwey scale used to measure it), acne and thinning scalp hair. It also looks at weight gain and insulin resistance, skin changes such as darkened patches and skin tags, and why pelvic pain is usually linked to related conditions like endometriosis rather than PCOS itself.

Not Started

lock

Chapter 4

The Diagnosis

What to expect when you are tested for PCOS. Because PCOS is a diagnosis of exclusion, the chapter starts with the conditions doctors rule out first, such as thyroid problems and raised prolactin. It then explains the three main steps in confirming a diagnosis: assessing symptoms, blood tests and a transvaginal ultrasound, including what the scan looks for and how the blood tests are grouped. It closes with practical advice on tracking your cycle and why working closely with your doctor matters, given how much the symptoms overlap with other conditions.

Not Started

lock

Chapter 5

Possible Causes of PCOS

Why PCOS develops. The exact cause is still unknown, so this chapter looks at the factors research has linked to it and how they feed into one another: family history and genetics, insulin resistance (which is common even in women who are not overweight), high androgen levels, chronic low-grade inflammation, and environmental and lifestyle influences such as diet and exposure to pollutants. It explains how these factors can create a cycle that keeps symptoms going and makes ovulation and pregnancy harder.

Not Started

lock

Chapter 6

Other Classification of PCOS

A look at another popular way of describing PCOS: four types based on the underlying driver. The chapter explains insulin-resistant PCOS, post-pill PCOS after stopping hormonal contraception, adrenal PCOS linked to stress hormones, and inflammatory PCOS, and what sets each apart. It is clear that this framework is not officially recognised or backed by strong clinical evidence, and explains its limits, while showing how it can still help you understand your own symptoms. The module closes with guidance on using what you have learnt to seek the right support.

Not Started

lock

Definition

According to the World Health Organisation (WHO), Polycystic Ovary Syndrome (PCOS) is the most common hormonal disorder among women of reproductive age and a leading cause of infertility.

While several definitions of PCOS exist, the Rotterdam Criteria is the most widely accepted. It defines PCOS as a condition involving ovarian dysfunction, often characterised by high levels of androgens (male hormones) and the presence of polycystic ovaries seen on ultrasound.

The History of PCOS

The history of Polycystic Ovary Syndrome (PCOS) dates back to 1935, when American gynaecologists Irving F. Stein, Sr. and Michael L. Leventhal first described the condition. They reported on women experiencing absent menstrual periods, excess hair growth, and enlarged ovaries with multiple cysts, features that would later define the syndrome.

Since their groundbreaking work, PCOS has been recognised and extensively studied worldwide, leading to a better understanding of its symptoms, causes, and treatments.

Prevalence of PCOS

According to the World Health Organisation (WHO), PCOS affects approximately 6 to 13% of women worldwide.

The exact prevalence varies by region; for example, it is estimated at 10.1% in China and around 11.4% in Southeast Asia. Despite these regional differences, the global average suggests that around 1 in 10 women are affected by PCOS.

Undiagnosed Women Fact

Despite its high prevalence, PCOS remains significantly underdiagnosed, with up to 70% of affected women unaware they have it.

According to the Women’s Health & Research Institute of Australia, PCOS itself typically doesn’t cause pain, and its symptoms, like irregular periods, acne, or weight gain, can be easily mistaken for other conditions. This makes diagnosis challenging without proper screening, and many women only discover they have PCOS when facing difficulties with fertility.

Introduction: Understanding PCOS

Understanding PCOS

Read chapter 1 on one page: Introduction

Definition

The History of PCOS

Prevalence of PCOS

Undiagnosed Women Fact