How Many Eggs Do Women Have During Their Lifetime?

Medically reviewed by Peter Weiss, MD

As people with ovaries age, their egg supply diminishes. Those concerned about fertility may find themselves doing mental gymnastics in an attempt to figure out how many eggs they have left. If that sounds like you, it may surprise you to learn that most of your egg supply disappeared before you were even born.

People with ovaries have around 1 million to 2 million eggs at birth. That number dips significantly by puberty and continues to decline until menopause.

In this article, we'll provide information about approximate egg quantity numbers by age. We'll also discuss conditions that may reduce egg supply, how birth control affects egg quantity, and the causes of reduced ovarian reserve before menopause.

Counting Female Eggs Before and After Birth

Figuring out how many eggs a woman has is not an exact science. Individual differences, certain health conditions, and lifestyle choices can impact both egg quantity and quality. There are, however, ballpark numbers that provide fairly accurate estimates about the number of eggs you may have at certain life stages and ages.

Terminology

In this article, the terms "woman" and "female" are used for people born with ovaries. Verywell Health respects that there are many ways a person may hold and express a sense of gender identity. This anatomic definition may not align with their gender identity.

In Uterus (Before Birth)

Prior to birth, female fetuses have between 6 million and 7 million oocytes (immature, developing eggs) in their ovaries. Most of these immature eggs will die off before birth through a natural process known as atresia. Atresia is an ongoing process that will continue to reduce your egg quantity throughout your reproductive lifetime.

At Birth

By the time a female is born, only around 1 million to 2 million oocytes remain in the ovaries.

Unlike other types of cells, egg cells do not regenerate once they are gone. Most medical experts agree that people are born with all their eggs and that no additional eggs will form.

First Period

Factors such as nutritional status, ethnicity, and weight can all affect when you get your menstrual period for the first time. In the United States, most people with ovaries get their first period at around age 12 or 13, although it's perfectly normal to start earlier or later.

Your first menstrual period occurs as part of the puberty process. During puberty, your body starts to produce hormones that support egg maturation and ovulation.

Atresia (egg death) continues to occur between birth and puberty. You will lose around 11,000 eggs monthly during these years.

By the time you have your first period, you will only have around 300,000 to 500,000 oocytes in your ovarian reserve. Of that number, around 300 to 500 will reach maturity over the course of your lifetime.

20s

Female fertility is typically at its highest peak during the late teen years through the late 20s. People in their 20s with ovaries typically have around 150,000 to 300,000 eggs left in their ovarian reserve.

People at this age usually have a significant quantity of high-quality eggs that can be fertilized and implanted in the uterus with relative ease.

30s

In many people, fertility starts to dip at around age 32, with a significant downswing between ages 35 and 37. By the time you reach 37, you'll have around 27,000 eggs remaining in your ovarian reserve.

In addition to quantity, egg quality also starts to recede during the 30s. This can make it harder for you to get or stay pregnant, even if you ovulate and menstruate regularly.

40s

Pregnancy can still occur during your 40s, but many people will be unable to conceive naturally without medical support during this time. By age 40, the number of eggs you have is estimated to be around 5,000 to 10,000.

Even with in vitro fertilization (IVF), people in this age group who attempt conception with their own eggs may have a hard time.

Data from the American College of Obstetricians and Gynecologists (ACOG) indicate that 12.4% of women aged 41 to 42 who do IVF with their own eggs will get pregnant and give birth. Between the ages of 43 and 44, 5% will give birth. After 44, that number dips to 1%.

50s Onwards

Menopause is defined by going one year without menstruating. During the transition to menopause, the period leading up to menopause, your egg supply will be gone, or almost gone. In the United States, the average age of menopause is 51.

In the year or so leading up to menopause, a person may have as many as 1,000 eggs. That may sound like a lot, but most or all of these will be of poor quality.

Pregnancy in women over 50 who used their own eggs is not unheard of. However, it's very rare.

How Many Eggs Does a Woman Produce Each Month?

Females are born with their entire egg supply. No new eggs are produced monthly. If you ovulate and menstruate regularly, you will typically release one mature, previously produced egg each month.

Monthly Number of Eggs Lost Each Period Cycle

Ovulation occurs around two weeks before menstruation. During the ovulation process, one mature egg is released from a follicle and out of an ovary. It then begins its journey down a fallopian tube for possible fertilization from sperm.

Occasionally, two (or more) eggs may mature and be released. If more than one egg becomes fertilized, fraternal (nonidentical) twins or triplets may be conceived.

Menstruating people lose around 1,000 additional eggs each month. These immature eggs remain encased in their follicles and die off to be absorbed naturally back into the body.

Not every person who menstruates has a monthly cycle. It's also possible to menstruate without ovulation taking place

People with conditions such as polycystic ovary syndrome (PCOS) may go many months without menstruating or ovulating. It's thought that even during anovulatory months (months without ovulation), immature eggs are lost to atresia.

Is IVF or Egg Freezing Reducing My Egg Supply?

If you're considering the use of assisted reproductive technologies like IVF or egg freezing, you may be concerned that they will "use up" your egg supply. Rest assured, that's not how these procedures work.

As already discussed, only one egg reaches maturity during a typical, natural ovulation. If you're doing IVF or having your eggs frozen, you'll be given medications that stimulate many immature eggs to maturity rather than just one. These eggs are the same ones that would have naturally died off that month. They are not "future" eggs that would have matured later on.

The bottom line is that assisted reproductive technologies do not reduce your egg pool.

What Affects How Many Eggs a Woman Has?

There is no proven strategy for increasing an existing egg supply. But there are lifestyle choices that may reduce your ovarian reserve and diminish fertility potential.

One of these is smoking. Data indicates that smoking cigarettes reduces your egg supply. It also diminishes the quality of your existing eggs.

Long-term, moderate alcohol consumption has also been shown to diminish ovarian reserve. The Centers for Disease Control and Prevention (CDC) categorizes moderate drinking for women as one or fewer alcoholic beverages per day.

Certain health conditions may also diminish egg supply or reduce egg quality. Endometriosis, an inflammatory condition that can cause infertility, has been found to reduce egg quality in some instances. This may be more likely to occur if endometriosis implants or endometriomas (chocolate cysts) are present in or on the ovary.

People who are fragile X premutation carriers may develop fragile X-associated primary ovarian insufficiency. This condition reduces the egg supply and can lead to infertility and early-onset menopause.

Medical treatments and other health conditions that may reduce ovarian reserve include:

• Primary ovarian insufficiency (formerly called premature ovarian failure)

• Chemotherapy

• Ovarian surgery

• Radiation therapy

• Pelvic infections
  

Birth Control and Egg Quantity

Hormonal forms of birth control include oral pills, implanted intrauterine devices (IUDs), patches, and injections. These forms of birth control work by stopping ovulation.

Birth control doesn't reduce your fertility potential once you stop taking it. It also doesn't delay menopause by "saving" your eggs.

Atresia, the process of egg diminishment, occurs even while you're taking birth control and not ovulating. So, you'll lose around 1,000 eggs a month while you're on the pill or any other form of hormonal birth control.

Egg Quality With Decreasing Quantity

Egg quality decreases with age, just like egg quantity.

Eggs prepare to mature by undergoing a phase of cell division called meiosis. The older your eggs get, the more likely they are to acquire DNA errors during this process. These changes to DNA alter the number of chromosomes each egg contains, causing genetic abnormalities within the egg.

Abnormal eggs are referred to as aneuploid. Aneuploidy affects 10% to 25% of eggs in people who are in their early 30s. It affects over 50% of eggs in people over 40.

Aneuploid eggs are less likely to result in a viable pregnancy, contributing to infertility. They’re more likely to lead to miscarriages or to conditions in fetuses and babies like Down syndrome.

Complications of Egg Decline Before Menopause

Primary ovarian insufficiency (POI) is sometimes referred to as early menopause. POI refers to the significant depletion or dysfunction of ovarian follicles, which contain immature eggs, in people under 40 years old.

People with POI stop ovulating and menstruating regularly. They may also have menopausal symptoms, like hot flashes and vaginal dryness. POI is not menopause, however.

Unlike menopause, which ends the possibility of natural pregnancy, 5% to 10% of people with POI get pregnant naturally. Since ovulation is very sporadic in this population, ovulation predictor kits and other strategies for attempting pregnancy may be ineffective.

How Do I Know How Many Eggs I Have Left?

Your healthcare provider can help you estimate your ovarian reserve through testing. These tests are usually reserved for people who are considering medical treatments for infertility.

Commonly used tests that may gauge your egg supply include:

• Antral follicle count sonogram: This vaginal ultrasound test lets your healthcare provider count the number of visible antral follicles you have. This provides information about the number of eggs you have remaining in your ovarian reserve. The amount of follicles you have will be referenced against the normal count for your age group.

• Follicle-stimulating hormone (FSH) blood test: FSH is a hormone that stimulates the growth of ovarian follicles. The lower your FSH, the more eggs you are thought to have in your ovarian reserve.

• Anti-Mullerian hormone (AMH) blood test: AMH is a hormone manufactured by the ovaries. High AMH levels indicate a large egg supply.

Summary

People with ovaries are born with all of the eggs they'll ever have, between 1 and 2 million. Egg supply diminishes naturally with age. People in their late teens through their early 20s have a high egg count with good egg quality.

Egg quantity and quality start to decline during the 30s, and continue to diminish until menopause occurs.

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