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The Fertility Patient’s Guide to Diminished Ovarian Reserve (DOR)

Authored and medically reviewed by Dr. Eli Reshef

Dr. Eli Reshef is a reproductive endocrinologist and fertility specialist who sees patients in Chicago and the greater Chicagoland area.

For many individuals and couples trying to conceive, fertility challenges can come as a surprise. One condition that often arises during fertility evaluation is diminished ovarian reserve (DOR)—a term that refers to a lower-than-expected quantity of eggs in the ovaries. While it may sound daunting, understanding DOR is the first step toward making empowered decisions about your reproductive health.

What Is Diminished Ovarian Reserve?

Diminished ovarian reserve means that the ovaries contain fewer eggs than expected for a person’s age, and those eggs may be less likely to result in a successful pregnancy. This decline in egg quantity and quality is a natural part of ovarian aging, but for some, it occurs earlier than anticipated primarily due to genetics, and infrequently due to environmental factors and/or surgery.  

Unlike primary ovarian insufficiency (POI), DOR does not mean the ovaries have stopped functioning. Many people with DOR still ovulate and may conceive naturally or with the help of fertility treatments.

Key Distinctions:

• DOR vs. POI: DOR is a gradual decline in egg quantity/quality, while POI involves premature cessation of ovarian function.

• DOR vs. Infertility: DOR is associated with reduced reproductive potential but not necessarily with infertility. People with infertility may have DOR, which may or may not be the true cause of their inability to conceive.

How Is Ovarian Reserve Measured?

Ovarian reserve is assessed using a combination of blood tests and ultrasound imaging during an initial fertility evaluation. These tests help fertility specialists tailor treatment plans and set realistic expectations.

Common Tests:

• Anti-Müllerian Hormone (AMH): AMH levels reflect the number of remaining follicles in the ovaries. Lower levels indicate reduced ovarian reserve. You can learn more about AMH testing here.

• Follicle-Stimulating Hormone (FSH) and Estradiol: Measured early in the menstrual cycle to evaluate how the ovaries respond to stimulation. Elevated FSH may signal poor ovarian response.

• Antral Follicle Count (AFC): A transvaginal ultrasound counts the number of small follicles in the ovaries, offering a visual estimate of egg supply.

These tests are not definitive on their own but offer valuable insights when interpreted together.

What Causes Diminished Ovarian Reserve?

While aging is the most common cause, diminished ovarian reserve (DOR) can result from a variety of biological, medical, and environmental influences. Here’s a closer look at each:

Aging

The number and quality of eggs naturally decline with age. By the mid-30s, this decline accelerates, and by the early 40s, both egg quantity and chromosomal integrity are significantly reduced. This is due to the finite number of follicles present at birth, which gradually decline over time.

Genetic Predisposition

Certain genetic conditions can lead to early depletion of ovarian follicles:

• Turner syndrome: Individuals with this chromosomal disorder often have underdeveloped ovaries and may experience premature ovarian failure.

• Fragile X premutation: Carriers of this genetic variation are at increased risk for premature ovarian insufficiency.

• Family history of early menopause: Suggests a hereditary component to accelerated ovarian aging.

Medical Treatments

Some medical interventions can directly damage ovarian tissue or disrupt follicular development:

• Chemotherapy: Targets rapidly dividing cells, including those in the ovaries, leading to follicular loss and hormonal disruption.

• Radiation therapy: Especially when directed at the pelvic region, can destroy ovarian follicles and impair hormone production.

• Ovarian surgery: Procedures to remove cysts or treat endometriosis may inadvertently remove healthy ovarian tissue or compromise blood flow, reducing reserve.

You can learn more about the impact cancer treatments have on fertility, as well as the preservation options that are available, in our dedicated blog.

Autoimmune Conditions

Diseases like lupus, rheumatoid arthritis, or autoimmune thyroiditis can trigger the immune system to attack ovarian tissue. This inflammation may lead to follicular damage or hormonal imbalances that impair ovarian function.

Lifestyle Factors

• Smoking: Toxins in cigarettes accelerate follicular depletion and increase oxidative stress in ovarian cells. This is the only known major environmental factor that may lead to DOR.

• Chronic stress: May disrupt the hypothalamic-pituitary-ovarian axis, affecting hormone levels and ovulation. This is a minor factor in DOR.

• Poor nutrition: Deficiencies in key nutrients like vitamin D, folate, and omega-3 fatty acids can impair reproductive health. This is a minor factor in DOR.

Environmental Exposures

Long-term exposure to endocrine-disrupting chemicals (EDCs)—found in plastics, pesticides, and industrial pollutants—may interfere with hormone signaling and follicular development.

Idiopathic (Unidentified) Cases

In some individuals, no clear cause is identified. These cases are termed idiopathic DOR, and they highlight the complex, multifactorial nature of ovarian aging.

Treatment Options for DOR

Having diminished ovarian reserve doesn’t mean pregnancy is impossible. Treatment options vary depending on individual circumstances and may include:

• In Vitro Fertilization (IVF): Often recommended to maximize the chances of fertilization with fewer eggs. Physicians may tailor stimulation protocols for low responders.

• Egg Donation: A viable option for those with very low egg counts or poor egg quality.

• Fertility Preservation: Egg or embryo freezing may be considered for those not ready to conceive but concerned about declining fertility.

• Ovulation Induction: Hormonal therapies to stimulate egg production.

• Lifestyle Optimization: Nutritional support, stress reduction, and toxin avoidance (especially smoking cessation) may help preserve ovarian function.

Success rates vary based on age, ovarian reserve levels, and overall reproductive health.

Emotional Support and Next Steps

Navigating DOR can be emotionally complex. At AFCC, we believe in compassionate, personalized care. Our team of board-certified reproductive endocrinologists specialize in assisted reproductive technologies, fertility preservation, and minimally invasive treatments.

We encourage early evaluation and open dialogue. Whether you're just beginning your fertility journey or exploring treatment options, our team is here to guide you every step of the way. Schedule your consultation today!

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