The ovaries are small, almond-shaped organs that play a central role in the female reproductive system, producing eggs and hormones like estrogen and progesterone. It is common for individuals to wonder if it is normal for one ovary to appear larger than the other. While slight size variations are often a natural occurrence, significant discrepancies can sometimes indicate underlying medical conditions.
Typical Ovary Size Differences
The size of ovaries can naturally fluctuate due to various physiological factors throughout a woman’s life. During the menstrual cycle, a dominant follicle develops in one ovary, growing to about 22-24 millimeters (0.87-0.94 inches) before releasing an egg. This temporary growth can make that ovary appear larger. Following ovulation, this follicle transforms into a corpus luteum, further contributing to temporary enlargement.
Ovary size also changes with age. In women of reproductive age, the average ovary measures 3-5 centimeters (1.2-2 inches) in length, 2-3 centimeters (0.8-1.2 inches) in width, and 1-2 centimeters (0.4-0.8 inches) in thickness. After menopause, due to declining hormone production and cessation of follicle development, ovaries generally decrease in size, often shrinking to less than 1 centimeter (0.4 inches). Minor individual variations between the left and right ovaries are normal and benign.
Medical Conditions Causing Ovary Size Discrepancy
Beyond normal physiological changes, several medical conditions can lead to a notable size difference between the ovaries. Ovarian cysts are a common cause; these are fluid-filled sacs that can form on or within an ovary. Functional cysts, such as follicular or corpus luteum cysts, develop as part of the menstrual cycle and usually resolve on their own. Other types, like dermoid cysts (containing tissue such as hair or skin) or endometriomas (filled with menstrual blood, often linked to endometriosis), can cause one ovary to be larger and may require intervention.
Polycystic Ovary Syndrome (PCOS) is another condition that can affect ovary size. Women with PCOS often have enlarged ovaries containing numerous small follicles, up to 8 millimeters (0.3 inches), which are underdeveloped sacs that do not regularly release eggs. This hormonal disorder can lead to symptoms such as irregular periods, excess hair growth, and acne. Endometriosis, where tissue similar to the uterine lining grows outside the uterus, can also cause endometriomas on the ovaries, leading to enlargement and symptoms like pelvic pain and painful periods. While some cysts are harmless, an enlargement beyond 4 centimeters (1.6 inches) can cause persistent discomfort and warrants medical attention.
When to Consult a Doctor
While minor variations in ovary size are normal, certain symptoms accompanying a size discrepancy warrant medical evaluation. If you experience persistent pelvic pain or pressure, a feeling of fullness or bloating in your lower abdomen, or changes in your bowel or bladder habits, consult a healthcare professional. These symptoms, especially if new or worsening, could indicate an underlying issue requiring diagnosis and treatment.
Other symptoms that should prompt a doctor’s visit include irregular menstrual cycles, unusually heavy bleeding, unexplained weight changes, or pain during sexual intercourse. Even if symptoms are mild, a medical professional can perform imaging tests, such as an ultrasound, to assess ovary size and identify any potential causes. Early diagnosis of conditions causing ovarian enlargement allows for appropriate management and can help prevent complications.