Ovarian Size: Understanding Normal and Enlarged Ovaries

Ovaries are typically symmetric, each measuring approximately 3 cm × 1.5 cm × 1.5 cm (volume 4–6 mL) in reproductive‑age women. Size varies with age, cycle phase, and hormonal status.

Asymmetry or Enlargement may indicate:

• Physiologic: Dominant follicle (up to 2–3 cm mid‑cycle), corpus luteum cyst.
• Pathologic: Polycystic ovary morphology (PCOM—≥20 follicles 2–9 mm or volume >10 mL), endometrioma, dermoid cyst, cystadenoma, ovarian torsion, malignancy.
• Hormonal: Stimulation (fertility drugs), hyperthecosis.

Transvaginal ultrasound is the standard for measurement. If an ovary is persistently enlarged, asymmetric, or has complex features, further evaluation (serial ultrasound, tumor markers CA‑125/HE4, MRI, referral to gynecologic oncology) is indicated.