What Causes PCOS? The 5 Key Factors Explained

Key Factors That Contribute to PCOS

1. Genetics^{1 2}

• If your mom, sister, or aunt has PCOS, you’re more likely to have it too
• It’s what scientists call a “polygenic disorder” – meaning multiple genes are involved, not just one
• These genes affect how your body handles insulin, produces hormones, and manages inflammation
• This explains why PCOS seems to “run in families” but doesn’t follow a simple inheritance pattern

2. Insulin Resistance^{3 4}

• 65–70% of women with PCOS have insulin resistance – your body needs more insulin to process sugar
• High insulin levels tell your ovaries to pump out more male hormones (androgens)
• This creates a vicious cycle: more androgens → more insulin resistance → even more androgens
• Even thin women with PCOS can have insulin resistance, though it’s more common with weight gain

3. Hormonal Imbalance^{5 6}

• In women with PCOS, LH (luteinizing hormone) levels are typically too high compared to FSH (follicle-stimulating hormone). *However, the LH/FSH ratio alone should not be used to diagnose PCOS because this ratio is not always elevated.^{7 8}
• This imbalance can interfere with ovulation and increase male hormone production
• Higher testosterone and other male hormones cause the hair growth, acne, and scalp hair loss

4. Weight Impact (But Doesn’t Cause PCOS)^{9 10}

• PCOS affects women of all sizes – thin, average, and overweight
• But carrying extra weight can worsen insulin resistance and hormone imbalances
• This might explain why some women notice their PCOS symptoms get worse with weight gain

5. Environmental and Lifestyle Triggers^{11 12}

• Early life factors like low birth weight might set the stage
• Chronic stress can worsen hormonal imbalances
• Diet and lifestyle habits may influence how severe your symptoms become
• Some research suggests environmental toxins might play a role, but this is still being studied

Why PCOS Varies So Much Between Women

PCOS is genetic predisposition meeting the unfortunate combination of hormonal, metabolic, and environmental factors.

This complex interaction explains why:

• Two sisters can both have PCOS but completely different symptoms
• Your symptoms might change over time or with lifestyle changes
• There’s no single “cure” – treatment focuses on managing the various factors
• What works for your friend with PCOS might not work for you

The Key Takeaway

References

1. The Application of Clinical Genetics – PCOS genetic factors and inheritance patterns
2. Trends in Endocrinology & Metabolism – Polygenic aspects of PCOS
3. Fertility and Sterility – Insulin resistance in PCOS pathophysiology
4. World Journal of Diabetes – Insulin resistance and androgen metabolism
5. Medical Archives – LH and FSH patterns in PCOS
6. Diagnostics – Hormonal imbalances in PCOS
7. Annals of Clinical Biochemistry – LH/FSH ratio diagnostic limitations
8. American Academy of Pediatrics – PCOS diagnosis and management
9. Cureus – Weight and PCOS relationship analysis
10. Journal of Clinical Endocrinology & Metabolism – Weight impact on PCOS
11. Journal of the Turkish-German Gynecological Association – Environmental and lifestyle factors in PCOS development
12. Human Reproduction Open – Birthweight and PCOS