Polycystic Ovarian Syndrome (PCOS)

Overview: PCOS is a complex, heterogeneous endocrine-metabolic disorder affecting women of reproductive age. It is a systemic condition involving hormonal imbalances, insulin resistance, and chronic low-grade inflammation.

1. Property and Definition

PCOS is diagnosed based on the Rotterdam Criteria, requiring at least two of the following:

Ovulatory Dysfunction: Irregular or absent ovulation.
Hyperandrogenism: Clinical signs (hirsutism, acne) or biochemical evidence (high testosterone).
Polycystic Ovaries: Observation of multiple small follicles (3-9mm) via ultrasound.

Prevalence: Affects approximately 4% to 21% of women worldwide.

2. Function and Manifestation

Reproductive Impact: A leading cause of infertility due to anovulation. Fewer than 9 periods a year can increase endometrial health risks.

Metabolic Impact: 60-80% of patients experience insulin resistance, leading to weight gain and difficulty with weight loss.

Physical symptoms often include excessive facial hair (hirsutism), severe acne, and scalp hair loss (alopecia).

3. Mechanism (Pathophysiology)

While the exact cause is unknown, it involves a mix of genetic and environmental triggers:

Neuroendocrine: Increased GnRH pulses lead to excess LH production, preventing follicle maturation.
Insulin-Androgen Cycle: High insulin levels stimulate ovaries to produce more androgens and suppress SHBG, increasing free testosterone.
Inflammation: Chronic low-grade inflammation and gut microbiome changes contribute to metabolic complications.

4. Long-term Health Risks

PCOS is a lifetime condition with significant risks beyond reproductive years:

Metabolic: Type 2 Diabetes, hypertension, and obesity.
Cardiovascular: Increased risk of atherosclerosis and heart events.
Oncology: Higher risk of endometrial hyperplasia and cancer.
Mental Health: High prevalence of anxiety, depression, and eating disorders.

Data sourced from NIH.gov, World Health Organization, and BMJ Medicine. 2026