What Women Should Know About Their Ovaries

The ovaries are egg-producing glands that are part of the female reproductive system. The ovaries are about the size and shape of an almond and sit just above the fallopian tubes—one ovary on each side of the uterus.

In a fertile person, every month during ovulation, either the right or left ovary produces a mature egg for fertilization. Typically, a single egg is released at a time, but in some cases, more than one egg can be released, resulting in the conception of multiples (i.e., twins or triplets).

Woman consulting with her gynecologist in the gynecologist's office
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Ovarian Follicles

At birth, a female baby has about 1,000,000 ovarian follicles. Each ovarian follicle contains a hollow ball of cells with an immature egg in the center.

During childhood, approximately half of the ovarian follicles are absorbed by the body. By the time of puberty and the beginning of an individual's menstrual cycle, only about 400,000 ovarian follicles are left to develop into mature eggs.

Although only one egg usually fully matures during each ovulation, somewhere between 10 and 20 follicles begin the process of maturation monthly. The excess ovarian follicles are reabsorbed before ovulation occurs.


Around the middle of the menstrual cycle (typically day 14 for a 28-day cycle, though this timing may vary), the process of ovulation is initiated and controlled by a drop in the hormone estrogen (mostly estradiol) and secretion of gonadotropin-releasing hormone (GnRH). This sends a message to the pituitary gland to increase its secretion of follicle-stimulating hormone (FSH). The increase in FSH causes the growth of 10 to 20 ovarian follicles.

Estrogen is secreted by some of the cells in the follicle. Just before ovulation occurs, the follicle that contains the maturing egg eases toward the surface of the ovary. Once the matured egg reaches the ovarian surface, ovulation occurs when the follicle and the ovarian surface open, allowing the egg to drift out of the ovary.

Additionally, progesterone is produced by the cells in the ovarian follicles shortly before ovulation occurs. After ovulation, if pregnancy has not occurred, the empty follicle is called the corpus luteum and it is reabsorbed into the body. If pregnancy does occur, the corpus luteum produces hormones that help to maintain the pregnancy.

After the egg is released from the ovary it travels to the oviducts (the funnel-shaped ends of the fallopian tubes) where it begins its long journey of several days into the uterus. The mature egg is moved along on its journey by wavelike muscle contractions in the fallopian tube.

The inner lining of each fallopian tube contains cilia which are constantly beating microscopic hairs; these cilia are what help move the sperm towards the egg if a person has had unprotected sexual intercourse.

Conception (the fertilization of an egg with sperm) most often occurs in the part of the tubes that is nearest the ovary. Five to six days are required for the fertilized egg to reach the uterus.

Eggs that are not fertilized either disintegrate or flow out of the body (unnoticed) with vaginal secretions.

Why Do My Ovaries Hurt?

You might experience a twinge, a cramp, or some discomfort in the lower back or abdomen when ovulation occurs. Some may notice a small amount of vaginal discharge, sometimes containing a small amount of blood, during ovulation.

Symptoms during ovulation are called mittelschmerz or midcycle pain. For some people, these symptoms are severe enough to be mistaken for an ectopic pregnancy or appendicitis. Others experience headaches, gastric pain, or general malaise, while still others actually feel much better during ovulation.

Ovarian Torsion

Rarely, an ovary can twist around the ligament holding it in place, known as ovarian torsion. This condition can result in severe pain and is considered a medical emergency, as the twisting (torsion) can cut off blood supply to the ovary and fallopian tube.

The initial symptoms are severe pelvic pain, typically on one side, along with nausea and vomiting. Immediate surgery is usually required to restore the blood supply and preserve the ovary from tissue death. Ovarian torsion may account for up to 3% of all gynecological emergencies.

Ovarian Cysts

Ovarian cysts are fluid-filled sacs, similar to blisters, that can form on the ovaries. Ovarian cysts are common during the reproductive years. Most types of ovarian cysts are harmless and go away without any treatment.

Polycystic Ovary Syndrome

Polycystic ovary syndrome (PCOS) is a hormonal disorder that affects an estimated 7% of all women. It is the most common hormonal disorder among women. According to experts, the actual number of people affected by PCOS may be as high as 1 out of 10 simply because so many cases remain undiagnosed.

Why are so many cases of PCOS undiagnosed? Since the symptoms can vary from person to person it is often difficult to accurately diagnose it. Because polycystic ovary syndrome can cause significant long-term health consequences, a quick and accurate diagnosis, followed by proper treatment, is urgent.

Ovarian Cancer

Ovarian cancer is often called the "silent" killer because many times there are no symptoms until the disease has progressed to an advanced stage. In the U.S., ovarian cancer ranks fifth in cancer deaths among women, making it the deadliest gynecological cancer.

Fallopian Tube Damage

Fallopian tubes that have been damaged by diseases, infections, or other conditions may be scarred, damaged, or destroyed, which sometimes can cause an ectopic (tubal) pregnancy to occur.

Some of the causes of fallopian tube damage include pelvic inflammatory disease (PID)endometriosis, or intrauterine devices (IUDs), as well as some sexually transmitted diseases (STDs) or other pelvic infections.

Frequently Asked Questions

Is it possible for both ovaries to release an egg in the same cycle?

Yes. Normally only one egg is released during ovulation, but it is possible for both ovaries to release an egg at the same time within the same cycle. If both those eggs become fertilized, they may result in fraternal (non-identical) twins.

What happens to ovaries during a hysterectomy?

A hysterectomy procedure involves removing the uterus, but in about half of all hysterectomies, healthcare providers will recommend that the ovaries be removed as well, in a procedure known as an oophorectomy. This may be recommended to reduce the risk of ovarian cancer, especially if you are considered high risk.

What causes ovarian cysts?

Ovarian cysts commonly form during ovulation or pregnancy. In some cases, they may result from hormonal treatments, including fertility treatments, or endometriosis (a condition in which uterine tissue may be found outside the uterus), or as a result of a pelvic infection.

How do you determine which ovary released the egg in a given cycle?

The simplest way to determine which ovary released the egg is by paying attention to any slight twinges of pelvic pain that may occur during your ovulation window, known as mittelschmerz. That slight pain on the right side or left side is likely the best indicator of which ovary released the egg.

What happens to ovaries after menopause?

After menopause, the ovaries stop releasing eggs and cease production of the hormone estrogen. However, they will still continue to produce testosterone alongside the adrenal glands. The ovaries become slightly smaller after menopause, but won't disappear.

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