Diminished ovarian reserve is a condition where a woman has fewer eggs remaining in her ovaries than expected for her age, or the quality of those eggs is reduced. This condition affects fertility and can make getting pregnant more challenging, though it doesn’t always mean pregnancy is impossible. Understanding this condition is the first step toward exploring your reproductive options.

Understanding Diminished Ovarian Reserve

Diminished ovarian reserve, sometimes called DOR or low ovarian reserve, occurs when your ovaries have fewer eggs or lower quality eggs compared to other women of the same age. Women are born with all the eggs they will ever have in their lifetime. This is different from men, who produce new sperm continuously. Your egg count starts at its highest point right after birth and naturally declines throughout your life until you reach menopause (the time when menstruation stops permanently).^[1]

At birth, a woman typically has between 1 and 2 million eggs. By the time puberty arrives, this number has already dropped to about 300,000 to 400,000 eggs. The decline continues as you age, with approximately 25,000 eggs remaining by age 40, and fewer than 1,000 eggs left at menopause.^[1] The rate of egg loss speeds up once you turn 35, which is one reason why age plays such a significant role in female fertility.^[1]

It’s important to understand that having diminished ovarian reserve doesn’t automatically mean you cannot get pregnant. It simply means that conception may be more difficult, and you might need to consider fertility treatment options sooner rather than later. You only need one healthy egg to achieve pregnancy, and factors beyond egg count also matter, including egg quality, sperm quality, and how well your uterus and fallopian tubes function.^[1]

How Common Is This Condition

Diminished ovarian reserve is more common than many people realize. Studies show that approximately 10 to 30 percent of women who seek help for infertility are diagnosed with DOR.^[4] However, this figure may not fully represent the general population, since many women with DOR never seek fertility treatment or remain undiagnosed until they try to conceive.^[19]

Age is the most significant factor affecting ovarian reserve. As women approach their late 30s and early 40s, the likelihood of experiencing diminished ovarian reserve increases dramatically. That said, DOR can affect women of all ages, including those in their 20s and early 30s. Sometimes this happens due to genetic factors, medical treatments, or reasons that remain unknown.^[1]

Recent research suggests that the diagnosis of DOR may be occurring more frequently than in the past. One study of women undergoing in vitro fertilization (IVF—a fertility treatment where eggs are fertilized outside the body) showed a 7 percent increase in DOR diagnoses between 2004 and 2011.^[7] This increase might be related to more women delaying childbearing until later in life, when diminished ovarian reserve is more likely to develop.^[7]

What Causes Diminished Ovarian Reserve

Aging is the primary cause of low ovarian reserve, but it’s not the only one. Every woman loses eggs as she ages, but some lose them faster than the general population, leading to a diagnosis of DOR. Natural fertility begins to decline as early as age 30, becoming more pronounced over the next decade. By the time women reach their mid-40s, few retain normal fertility levels.^[4]

Beyond normal aging, several other factors can contribute to diminished ovarian reserve. Genetic disorders that affect the X chromosome can lead to earlier egg loss. One important example is Fragile X syndrome, an inherited condition that not only causes early ovarian failure but is also the most common inherited cause of intellectual disability and autism. Women with DOR should be screened for this condition.^[4]

Medical treatments, particularly those for cancer, can damage the ovaries and reduce egg supply. Both chemotherapy and radiation therapy directed at the pelvic area can harm ovarian tissue and decrease the number of viable eggs.^[1] Surgery on the ovaries, such as procedures to remove ovarian cysts or treat endometriosis (a condition where tissue similar to the uterine lining grows outside the uterus), can also reduce ovarian reserve, especially if large amounts of ovarian tissue need to be removed.^[3]

Autoimmune conditions represent another cause. In some cases, the body’s immune system mistakenly attacks ovarian tissue, impairing its function and reducing the number of healthy eggs.^[1] Severe endometriosis itself can affect ovarian reserve and egg quality, making conception more challenging.^[6] Previous pelvic infections and injuries to the ovaries have also been linked to diminished ovarian reserve.^[3]

In many cases, however, there is no apparent cause for diminished ovarian reserve. This is called idiopathic DOR, meaning the underlying reason remains unknown despite thorough investigation.^[3]

Risk Factors That Increase Your Chances

Certain groups of women face higher risk of developing diminished ovarian reserve. Understanding these risk factors can help you make informed decisions about your reproductive timeline and when to seek help from a fertility specialist.

Age remains the most significant risk factor. Women aged 35 and older face increased likelihood of diminished ovarian reserve, with the risk rising substantially after age 40.^[8] However, younger women are not immune to this condition, especially if other risk factors are present.

Lifestyle choices also play a role. Cigarette smoking is one of the most significant modifiable risk factors for diminished ovarian reserve. The chemicals in cigarettes accelerate egg loss, and the impact increases with the number of cigarettes smoked per day. Smoking can lead to earlier menopause and reduced fertility throughout a woman’s reproductive years.^[3] According to the American Society of Reproductive Medicine, smoking and tobacco use are the only lifestyle factors definitively associated with decreased ovarian reserve.^[1]

Women with a family history of early menopause face higher risk. If your mother or sisters experienced menopause before age 40, you may be predisposed to losing eggs at a faster rate.^[6] This genetic component means that your biological clock may tick faster than average, even if you’re otherwise healthy.

Previous cancer treatment puts women at substantial risk. Both chemotherapy drugs and radiation therapy can permanently damage the ovaries, particularly when treatment occurs during childhood or young adulthood.^[1] Women who have undergone such treatments should consider having their ovarian reserve tested, especially if they wish to have children in the future.

Certain medical conditions increase risk as well. Autoimmune diseases, where the body attacks its own tissues, can target the ovaries. Women with conditions like lupus or thyroid disorders may experience accelerated egg loss.^[1] Similarly, women who have had surgery on their ovaries for any reason, including removal of cysts or treatment of endometriosis, face increased risk of diminished ovarian reserve.^[9]

Symptoms to Watch For

One of the most challenging aspects of diminished ovarian reserve is that most women have no obvious symptoms. For many, the first sign of a problem is difficulty getting pregnant after several months or years of trying to conceive through regular sexual intercourse.^[1] This means you might not know you have DOR until you actively attempt to start a family.

Some women do notice changes in their menstrual cycles. The most common symptom is a consistently shorter menstrual cycle. For example, if your cycle previously ran 28 days from start to finish, it might shorten to 24 or 25 days.^[4] This happens because when egg reserve is low, the ovaries try to protect their remaining eggs, and this changes the hormone patterns that control your cycle.

As the condition progresses and approaches primary ovarian insufficiency (when the ovaries stop working properly before age 40), some women begin experiencing symptoms similar to menopause. These can include hot flashes, which are sudden feelings of warmth spreading through your body, often accompanied by sweating. Night sweats may disrupt your sleep.^[1]

Other symptoms that may appear include irregular menstrual periods or skipped periods altogether. Some women notice vaginal dryness, which can make intercourse uncomfortable. Irritability, difficulty concentrating, and decreased interest in sex may also occur.^[14] These symptoms result from lower estrogen levels, which happen when the ovaries have very few eggs remaining and aren’t functioning as actively as they should.

It’s worth noting that experiencing one or more of these symptoms doesn’t automatically mean you have diminished ovarian reserve, as they can overlap with other reproductive health conditions. The only way to confirm a diagnosis is through fertility testing conducted by your healthcare provider.^[6]

Ways to Lower Your Risk

While some causes of diminished ovarian reserve cannot be prevented, particularly those related to genetics and normal aging, certain steps can help protect your ovarian reserve and optimize your fertility for as long as possible.

The most important preventive measure is to avoid smoking. If you currently smoke, quitting is one of the best things you can do for your fertility. Smoking accelerates egg loss and can lead to earlier menopause. The damage from smoking is dose-dependent, meaning the more you smoke, the greater the harm to your eggs. Even secondhand smoke exposure should be minimized when possible.^[3]

If you’re facing cancer treatment, discuss fertility preservation options with your healthcare team before beginning chemotherapy or radiation. Modern fertility medicine offers egg freezing and other preservation techniques that can help protect your future fertility. These conversations should happen as early as possible in your cancer treatment planning.^[9]

Awareness of your family history matters. If you know that women in your family experienced early menopause or had difficulty conceiving, consider having your ovarian reserve tested earlier than you might otherwise. This knowledge allows you to make informed decisions about your reproductive timeline and whether you might benefit from earlier family planning or egg freezing.^[6]

Regular check-ups with your healthcare provider are important, especially if you have autoimmune conditions or other health issues that might affect your ovaries. Proper management of underlying health conditions can sometimes help preserve ovarian function.^[1]

While there’s no evidence that diet, exercise, or supplements can prevent age-related decline in ovarian reserve, maintaining overall good health supports your body’s systems, including your reproductive system. This means eating a balanced diet, staying physically active, managing stress, and getting adequate sleep.

If you know you want children someday but aren’t ready now, especially if you’re in your 30s or have risk factors for DOR, consider meeting with a fertility specialist for baseline ovarian reserve testing. This doesn’t commit you to any treatment, but it gives you information to help plan your reproductive future. Some women choose to freeze their eggs when they’re younger, particularly if they know they won’t be ready to have children until their late 30s or 40s.^[9]

How the Body Changes With This Condition

To understand how diminished ovarian reserve affects your body, it helps to know how healthy ovarian function normally works. Each month during your reproductive years, your ovaries offer up a group of eggs for potential pregnancy, regardless of whether you’re actively trying to conceive. Your brain releases hormones, particularly follicle-stimulating hormone (FSH), which acts like nourishment for these eggs to help them grow and mature.^[21]

Under normal circumstances, your brain produces only enough hormone to fully mature one egg. That single egg grows, develops, and is released during ovulation. The other eggs from that month’s group don’t receive enough hormonal support, so they essentially disappear. This is why humans typically have one baby at a time, rather than litters like some other species. Many eggs are naturally wasted each month as part of normal biology.^[21]

When you have diminished ovarian reserve, your ovaries can sense that the egg supply is running low. In response, they offer up fewer eggs each month in an effort to preserve the remaining reserve. This protective mechanism means that on ultrasound examination early in your menstrual cycle, doctors see fewer developing egg follicles than would be expected for your age. This measurement is called the antral follicle count (AFC).^[21]

The hormonal communication between your brain and ovaries also changes with DOR. When the ovaries are reluctant to release eggs, your brain tries harder to stimulate them by producing more FSH. Think of it like your brain sending out more “food” to entice the follicles to emerge. This means women with diminished ovarian reserve often have higher than normal FSH levels, particularly when measured early in the menstrual cycle.^[1]

The very small eggs waiting in your ovaries also secrete a hormone called anti-Müllerian hormone (AMH) into your bloodstream. When you have many eggs in reserve, AMH levels are higher. As your egg supply diminishes, less AMH is produced, resulting in lower blood levels. Unlike other fertility hormones, AMH stays relatively steady throughout your menstrual cycle, making it a reliable marker of ovarian reserve at any time of the month.^[21]

It’s crucial to understand the difference between egg quantity and egg quality, as both matter for fertility and both are affected by DOR. Egg quantity refers to how many eggs remain in your ovaries, while quality refers to the structural integrity of each egg and whether it contains the correct genetic information to create a healthy pregnancy. Unfortunately, both quantity and quality decline with age, though they follow different patterns.^[21]

Egg quantity falls in a steady, predictable pattern during your reproductive years. Egg quality, however, remains relatively stable through your 20s and early 30s, then begins to decline more noticeably in your mid-30s, with a sharper drop around age 40. This decline in quality explains why older eggs have higher rates of chromosomal abnormalities, which can lead to failed implantation, miscarriage, or birth defects.^[21]

When both egg quantity and quality are reduced, as often happens with DOR, the chances of successful conception decrease. Even with fertility treatments like IVF, where multiple eggs can be retrieved and fertilized, women with diminished ovarian reserve face greater challenges because they produce fewer eggs, and a higher proportion of those eggs may have quality issues.^[3]