A slight variation in ovarian size is often normal and typically not a cause for concern. This article clarifies why these size differences occur, distinguishing between normal physiological changes and situations that might warrant medical attention.
Ovarian Basics
Ovaries are small, oval-shaped glands located on either side of the uterus in the lower abdomen. They play a dual role in the female reproductive system. Ovaries produce and release eggs for potential fertilization, a process known as ovulation. They also produce hormones, primarily estrogen and progesterone, which regulate the menstrual cycle and support pregnancy.
Typical Size Differences
One ovary being slightly larger than the other is common and a normal part of ovarian function. Ovarian size fluctuates throughout the menstrual cycle due to physiological processes.
During the follicular phase, a dominant follicle grows, temporarily increasing the size of the ovary where it develops. After ovulation, the ruptured follicle transforms into a corpus luteum, which also contributes to temporary enlargement. These changes are part of the natural preparation for potential pregnancy and typically resolve on their own. Functional cysts, fluid-filled sacs that form during the menstrual cycle, are also common, usually benign, and often resolve without intervention.
Reasons for Significant Size Variation
While minor fluctuations are normal, a more pronounced or persistent difference in ovarian size can indicate an underlying medical condition. Certain ovarian cysts, such as endometriomas or dermoid cysts, can cause one ovary to become noticeably larger. Endometriomas form when endometrial tissue grows on the ovary. Dermoid cysts, also known as teratomas, can contain various tissues like hair, skin, or teeth, and may exceed 10 centimeters (cm).
Polycystic Ovary Syndrome (PCOS) is another common condition leading to enlarged ovaries, often characterized by multiple small follicles. These ovaries can be 1.5 to 3 times larger than normal, with an ovarian volume greater than 10 cubic centimeters (cm³). Less commonly, benign or malignant tumors can also cause significant ovarian enlargement. Ovarian edema, a rare condition where fluid builds up in the ovarian tissue, often affects only one ovary, causing it to enlarge.
When to Consult a Doctor
Consult a healthcare professional if you notice persistent symptoms alongside a size difference in your ovaries. Symptoms warranting medical evaluation include ongoing pelvic pain, abdominal bloating or swelling, changes in menstrual cycles, or pain during sexual intercourse. Other concerning signs include feeling full quickly when eating, changes in bowel habits, or frequent urination.
A doctor may perform a physical exam, including a pelvic exam, to check for abnormalities. Imaging tests, such as transvaginal or abdominal ultrasound, are commonly used to visualize the ovaries and assess their size and structure. Blood tests, including those for specific markers like CA-125, may also be conducted, though elevated CA-125 levels can be caused by conditions other than cancer. These evaluations help determine the cause of the size variation and guide appropriate management.