Diminished Ovarian Reserve

What is diminished ovarian reserve?

Diminished ovarian reserve (DOR), also called low ovarian reserve, is the condition when a woman’s ovaries have fewer eggs remaining, or fewer good quality eggs remaining, than other women of a similar age. A woman is born with a finite number of eggs, called the ovarian reserve, which decreases naturally as she ages.

However, both a low number of eggs and poor quality of the eggs can result in infertility. This is due to unsuccessful fertilization, failure of the embryo to implant in the uterus for pregnancy and miscarriage.

We administer tests to determine both the number and quality of eggs in the ovarian reserve. This helps us understand if the ovaries are aging at an increased rate, the potential onset of reduced fertility, and the possible success of in vitro fertilization (IVF) or other treatments to address infertility.

As in natural attempts at successful pregnancy, DOR also decreases the chance of pregnancy through IVF, which has nothing to do with reversing declines in egg quantity or quality.

The natural rate of oocyte (egg) decrease, from the American College of Obstetrics and Gynecologists:

• 6-7 million eggs in a 20-week-old fetus.
• 1-2 million at birth.
• 300,000-500,000 at puberty.
• 25,000 at age 37.
• 1,000 at 51, the average beginning of menopause in this country.

The rate of decrease accelerates around age 32 and is a predominant reason age impacts female fertility. Though the decline in egg number and quality occurs naturally, the diagnosis of DOR indicates that decline is pronounced and should be addressed if the woman desires to have children.

It’s important to note that low ovarian reserve can occur at different ages for women, and that age appears to be getting younger, though more research is needed in this area. DOR is also occurring more often, due to women waiting until a later age to have a child than previously for a variety of reasons. This advanced age makes DOR more likely when women do try to get pregnant. One study of IVF patients shows a 7% increase in DOR from 2004 to 2011.

What causes diminished ovarian reserve?

Three factors cause diminished ovarian reserve:

• The woman is born with less than the average number of eggs and/or they are of abnormal quality.
• The number of eggs or their quality declines faster than in other women at similar points of age.
• The eggs experience more damage than normal over time.

No matter what a woman does, she loses eggs every day. As mentioned, this loss increases as she ages. The degradation of the remaining eggs’ quality also increases with age because the eggs, as well as the supporting cells around them, accumulate damage that affects their ability to result in a pregnancy.

Age-damaged eggs often lower the chance of getting pregnant and maintaining it, while also increasing the chance of birth defects.

When assessing the ovarian reserve, fertility specialists can see that as women age, the percentage of poor quality eggs to good quality eggs increases. This means the chance for pregnancy failure also increases.

In addition to natural causes of low ovarian reserve, existing conditions and treatments can cause DOR.

• Autoimmune disease, which can attack the ovaries.
• Genetic disorders with the x chromosome like Fragile X premutation.
• Radiation or chemotherapy cancer treatments.
• Surgery on the ovaries.
• Loss of one or both ovaries due to disease like endometriosis, cysts or ovarian torsion.

Fertility specialists can’t always determine a cause for DOR.

Ovarian reserve testing

Most people don’t have symptoms of DOR to indicate they should be tested. Sometimes a woman may notice that her menstrual cycles are getting shorter, which may be a symptom of DOR. The main reason to seek testing is failure to get pregnant. Women who have experienced the conditions listed above or who have been trying to get pregnant for a year without success (after six months of trying for a woman over 35) should consider DOR testing.

We utilize different tests to determine low ovarian reserve. Assessing the level of key reproductive hormones is one way to test for DOR and transvaginal ultrasound is another. The ovarian reserve testing results can tell us whether the individual has decreased fertility potential. It also indicates the chances of successful pregnancy using IVF, which is a major reason we conduct ovarian reserve testing.

A diagnosis of DOR does not mean a woman can’t get pregnant naturally or with fertility treatments. All it takes is ovulating one good egg. Our evaluation of DOR can help people decide if they might be better off trying IVF to increase their chances.

Antral follicle count

An antral follicle count evaluates the number of mature follicles, which are groups of cells that contain an egg and keep it nurtured. Using transvaginal ultrasound, we can detect the number of mature follicles a woman has during her cycle, usually conducting the test on day three of her menstrual cycle if possible. Mature follicles collect fluid around them that shows up on ultrasound. More follicles are a good sign; fewer than 10 follicles on both ovaries combined will bring a diagnosis of diminished ovarian reserve.

Anti-Müllerian hormone test

The anti-müllerian hormone (AMH) is secreted by the follicle as it comes out of the storage pool in the ovary. Detecting higher levels of AMH is an indication that a higher number of follicles is emerging from storage. This high AMH level allows us to predict that stimulation during IVF will result in a good number of eggs to be retrieved. Low levels of anti-müllerian hormone indicate low ovarian reserve.

Follicle-stimulating hormone level & estradiol level testing

Testing follicle-stimulating hormone (FSH) levels and estradiol (estrogen) levels through blood samples is a key way fertility specialists evaluate low ovarian reserve. High FSH levels compared to other women of the patient’s age indicate the ovary is not functioning properly. This suggests the chance of a live birth is not very good, even if using ovulation stimulation in IVF. We evaluate estradiol levels as a way to validate our FSH level findings. Both levels measuring in the normal range is a good sign.

A less commonly used evaluation for DOR is the clomiphene citrate challenge test, which can find cases of low ovarian reserve when the other tests indicate there is no problem. Clomiphene citrate is a fertility drug that stimulates hormones that support ovulation. When given to a woman who responds to it, this indicates normal ovarian function.

Treatment for DOR

Freezing eggs may be advised for younger women who are at high risk of diminished ovarian reserve. The frozen eggs can be used later when their eggs and/or their quality have declined further and likely to not result in pregnancy.

Superovulation, an enhanced form of ovulation induction, uses medications to promote the production of multiple eggs that can be used in IVF.

Using donor eggs with IVF is another solution.