VHOSPITAL.CLINIC · Differential Diagnosis
Endometriosis vs PCOS (Polycystic Ovary Syndrome)
Clinical comparison — shared symptoms, key differences, distinguishing diagnostic tests, treatment pathways, and when to seek urgent evaluation.
Condition Overview
Condition A
Endometriosis
Endometriosis is a condition where tissue similar to the uterine lining grows outside the uterus. It causes chronic pelvic pain, especially during menstruation, and can lead to infertility. It affects approximately 10% of reproductive-age women.
Condition B
PCOS (Polycystic Ovary Syndrome)
Polycystic ovary syndrome (PCOS) is a hormonal disorder common among women of reproductive age, causing irregular periods, excess androgen levels, and polycystic ovaries. It is associated with insulin resistance and increased risk of diabetes and heart disease.
Shared Symptoms — Why They're Confused
Both conditions present with 3 overlapping symptoms, making clinical differentiation essential.
Key Clinical Differences
Endometriosis
- Cyclical dysmenorrhoea and chronic pelvic pain
- Infertility from anatomical distortion or adhesions
- Normal hormonal profile
- Laparoscopic diagnosis
PCOS (Polycystic Ovary Syndrome)
- Irregular or absent periods from chronic anovulation
- Androgen excess: hirsutism, acne, alopecia
- Polycystic ovarian morphology on ultrasound
- Insulin resistance and metabolic syndrome
Distinguishing Diagnostic Tests
| Test | Endometriosis | PCOS (Polycystic Ovary Syndrome) |
|---|---|---|
| Hormonal profile (LH/FSH/testosterone) | Normal hormones — no androgen excess or LH:FSH imbalance | LH:FSH >2:1; elevated free testosterone; insulin resistance |
| Pelvic ultrasound | Endometrioma (chocolate cyst) in ovary; no follicular necklace | ≥12 follicles/ovary (antral follicle necklace), increased ovarian volume |
| Menstrual pattern | Regular periods, often with severe dysmenorrhoea | Oligomenorrhoea or amenorrhoea from anovulation |
Treatment Approaches
Endometriosis
- •GnRH agonists, combined OCP, progestins
- •Laparoscopic excision for fertility or pain
PCOS (Polycystic Ovary Syndrome)
- •OCP for cycle regulation
- •Metformin for insulin resistance
- •Letrozole/clomiphene for ovulation induction
When Doctors Consider Each Diagnosis
🔵 Consider Endometriosis when:
- →Regular dysmenorrhoeic cycles, normal hormones, endometrioma on USS
🟢 Consider PCOS (Polycystic Ovary Syndrome) when:
- →Irregular anovulatory cycles, hirsutism, LH:FSH imbalance, PCOM on USS
Explore Each Condition in Detail
Related Clinical Pages
Endometriosis
PCOS (Polycystic Ovary Syndrome)
Medical References
Content on this page is informed by evidence-based clinical sources including:
- World Health Organization (WHO)Global health guidance and disease classification
- National Health Service (NHS)UK clinical guidelines and patient information
- National Institute for Health and Care Excellence (NICE)Evidence-based clinical practice guidelines
- Centers for Disease Control and Prevention (CDC)US public health data and clinical recommendations
- PubMed – NCBIPeer-reviewed biomedical literature and clinical studies
- Cochrane LibrarySystematic reviews and meta-analyses in evidence-based medicine
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