The ovaries are two small, almond-shaped organs that produce eggs and essential hormones like estrogen and progesterone. While generally similar in size, their dimensions vary throughout life and the menstrual cycle. Many of these size differences are natural.
Normal Physiological Variations
Ovarian size naturally fluctuates with the menstrual cycle. In adulthood, ovaries typically measure 2-5 cm in length, 1-2 cm in width, and 0.5-1.5 cm in thickness.
During the follicular phase, ovaries are largest as follicles develop. A dominant follicle, a fluid-filled sac with an egg, can reach 18-28 millimeters (1.8-2.8 centimeters) before releasing the egg.
After ovulation, the ruptured follicle becomes a corpus luteum, which produces hormones and temporarily increases ovarian size. The dominant ovary’s volume increases during the follicular and luteal phases, while the non-dominant ovary typically shows no significant size changes.
Age also influences ovarian size. Volume increases through adolescence, peaks around age 20, then gradually declines. With menopause, ovaries stop producing eggs and hormones, noticeably reducing in size, often becoming non-palpable. For instance, ovarian volume can decrease from approximately 8.6 cm³ in the first year after menopause to about 2.2 cm³ after more than 15 years.
Medical Conditions Affecting Size
Beyond normal physiological changes, several medical conditions can enlarge ovaries. Ovarian cysts are a common cause: fluid-filled or semi-solid sacs on or within the ovaries. Many are functional, forming as a normal part of the menstrual cycle and typically resolving within a few months. These functional cysts, like follicular and corpus luteum cysts, are usually small, often under 1.5 centimeters, though some can exceed 2.5 centimeters.
Other ovarian cysts, pathological cysts, are not cycle-related and enlarge the ovary. Dermoid cysts are benign tumors containing hair, skin, or fat; though slow-growing, they can become large. Cystadenomas are benign growths on the ovary’s surface, filled with watery or mucous fluid, some reaching up to 30 centimeters. Endometriomas, or “chocolate cysts,” form when uterine-lining-like tissue grows on the ovaries, creating dark fluid-filled cavities. These range from 2-5 centimeters, but some can exceed 15 centimeters.
Polycystic Ovary Syndrome (PCOS) can enlarge ovaries. Individuals with PCOS have hormonal imbalances leading to multiple small follicles (sometimes called cysts) on the ovaries. These follicles, typically 2-9 millimeters, increase ovarian volume; a volume over 10 mL is often a diagnostic criterion. While many with PCOS have enlarged ovaries, the degree of enlargement varies.
Less commonly, benign or malignant tumors can cause ovarian enlargement. Benign ovarian tumors, such as fibromas, generally grow slowly and rarely spread. Ovarian cancer, while less frequent, can present with an enlarged ovary. Early stages of ovarian cancer often have vague or no noticeable symptoms, making early detection challenging.
When to Consult a Healthcare Professional
While ovarian size differences are often normal, certain symptoms warrant professional evaluation. Seek medical attention for persistent pelvic pain or discomfort, if severe or unusual. Other concerning symptoms include unresolved abdominal bloating or swelling, changes in bowel habits (like persistent constipation or diarrhea), or changes in urinary frequency or urgency.
Unexplained weight loss, feeling full quickly after eating small amounts, or abnormal vaginal bleeding (especially between periods or after menopause) should prompt a medical consultation. These symptoms, while potentially related to less serious conditions, can sometimes indicate an underlying issue requiring investigation. Regular gynecological check-ups are important for overall reproductive health, providing an opportunity for early detection of potential abnormalities.
Ovarian size differences are often discovered incidentally during imaging tests, like ultrasounds. If such findings occur, further evaluation may be necessary to determine the cause and appropriate management. Always discuss any health concerns with a doctor, as they can provide an accurate diagnosis and guide necessary steps.