How many eggs does a woman have? Ovarian reserve, ovulation, and age explained simply

Quick answer: the ovarian reserve is finite

The ovaries contain a stock of resting eggs inside follicles. This stock is established before birth and then steadily declines. Toward the end of the reproductive years, around menopause, only very few of these resting follicles remain.

You cannot directly count how large the reserve is in one person. Medicine and research therefore use models and tests that provide an estimate. A very accessible overview with typical orders of magnitude is available in the Merck Manual. A scientific modeling across the lifespan can be found in Wallace and Kelsey (2010).

The essentials at a glance

• The ovarian reserve is finite and declines over time.
• Most cycles release only one egg, while many follicles are broken down beforehand.
• AMH and antral follicle count estimate quantity, not the genetic quality of individual eggs.
• Age strongly affects egg quality, regardless of how high the reserve is.
• If pregnancy does not happen, an evaluation can be helpful: often after 12 months, earlier if you are 36 or older or if risk factors are known. See NHS and NICE QS73.
• There are many paths, from good cycle timing to treatment, and they need to fit the personal situation.

Reference values: rough orders of magnitude by life stage

If you search for the number of eggs, you usually want a number. But there is no single number that fits everyone. The following ranges are only for orientation and can differ substantially from person to person.

• Around the 20th week of pregnancy: often 6 to 7 million are cited.
• At birth: usually 1 to 2 million.
• At puberty: roughly 300,000 to 500,000.
• Around age 37: as an order of magnitude about 25,000.
• Around menopause: as an order of magnitude about 1,000. In Wallace and Kelsey (2010), menopause is described on average at 50 to 51 years.
• At 30 and at 40: In Wallace and Kelsey (2010), for 95 percent of women about 12 percent of the maximum reserve remains at 30 and about 3 percent at 40.

Important: these numbers describe the pool of resting follicles, not the number of ovulations. Over a lifetime, only a few hundred eggs are actually ovulated. A clear overview is provided, for example, by the Merck Manual.

What do these numbers actually mean?

In studies and models, the focus is usually on non-growing follicles in the ovary. This is the stock of resting eggs from which, in each cycle, a small group starts to mature. These resting follicles are not the same as the eggs that are currently growing in that cycle.

Also, these numbers are not blood test results and not a direct measurement in one individual. They are estimates from histological studies and models derived from them. They help you understand orders of magnitude, but they do not replace individual assessment.

Are women born with all their eggs?

In principle, yes. The pool of resting follicles is established before birth. After that it is not replenished, it declines. This concept is the basis for many models of ovarian reserve across the lifespan.

There is research on whether stem cell mechanisms could exist in the ovary. But for practical fertility counseling, it is still assumed that the pool is not newly formed in everyday life.

How many eggs mature per cycle?

In each cycle, several follicles start to develop in the ovary. Usually, one dominant follicle prevails in the end. The rest regress. This explains why the ovarian reserve declines much faster than the number of ovulations.

Put simply, only a very small proportion of follicles are ovulated, while most are broken down through follicular atresia. This is also described in reviews on follicle development and atresia, for example in Zhou et al. (2019).

If you want to understand the process in more detail, read our article on ovulation.

How many eggs are released at ovulation?

In most cycles, exactly one egg is released. Sometimes two dominant follicles mature at the same time and then two eggs can ovulate. This is a prerequisite for fraternal twins.

How can you estimate ovarian reserve today?

Clinicians cannot count the ovarian reserve exactly, but they can often estimate it meaningfully. Two established building blocks are:

• AMH blood test: anti-Müllerian hormone is produced in small follicles. The level can provide hints about the current follicle pool size.
• Antral follicle count, abbreviated AFC: on ultrasound, the small visible follicles are counted. This is another indicator of reserve.

Both methods are estimates and do not directly tell you whether an individual egg is genetically healthy. They mainly help to put the situation in context and to plan next steps. For guidance, see for example NICE CG156 and NHS information on infertility.

When does an AMH test or ultrasound make sense?

Many people want testing because they want reassurance. That is understandable, but the key question is what you need the information for. A test can be useful if you need to plan your timeline or if you have specific symptoms or risks.

• You are 36 or older and you are trying to get pregnant.
• Your cycles become clearly shorter or irregular.
• You have had ovarian surgery, chemotherapy, radiation, or a known condition that can affect the ovaries.
• You are considering freezing eggs and want to plan realistically.

If an AMH result worries you, the next step is rarely a second test alone. It is usually more helpful to interpret it together with ultrasound findings, cycle pattern, and your age.

What happens to egg quality with age?

As age increases, the risk that an egg carries chromosome errors increases. This can reduce the chance that fertilization leads to a healthy embryo. That is why age is one of the strongest factors for the chances of pregnancy, especially from the mid 30s onward.

A high AMH level does not automatically mean that egg quality stays young. It mainly reflects the quantity of recruitable follicles. For a broader overview of age, reserve, and options, see fertility and age.

Ovarian reserve and pregnancy: what really matters

A smaller reserve does not automatically mean you cannot get pregnant. But it can mean the time window is narrower and fewer attempts are possible. Conversely, a large reserve does not guarantee pregnancy, because factors like fallopian tubes, uterus, ovulation, sperm quality, and cycle timing also matter.

If you want a clear plan, a simple order often helps: first understand your cycle and timing, then get a targeted evaluation, and only then talk about treatment steps. This adds structure and prevents getting stuck on single numbers.

Can you improve egg quality?

You cannot stop biological aging. There is also no method that has been proven to clearly improve egg quality. What you can influence are factors that add additional strain to fertility.

• Avoid or quit smoking, because it can negatively affect ovarian function. See also smoking and fertility.
• Drink alcohol only in moderation, especially when trying to conceive. See also alcohol.
• If you have prolonged cycle irregularity, very short cycles, or you have been trying without success, get an early medical evaluation.

What are signs of low ovarian reserve?

In many cases there are no clear symptoms. Some people notice shorter cycles or changed bleeding, but that is nonspecific. Often, low reserve is only noticed when pregnancy takes longer than expected.

Can you get pregnant with low reserve?

Yes, it is possible. In the end, you only need one egg that can be fertilized. A lower reserve can mean that fewer attempts are possible and that time plays a bigger role.

If you want support, depending on the situation, cycle optimization, IUI, IVF, or ICSI can be options to discuss in a consultation.

What happens to the eggs that are not ovulated?

Most follicles do not make it to ovulation. They are broken down and reabsorbed by the body. Nothing builds up. This also explains why the reserve declines over time even if there are fewer ovulations. The loss mainly happens because many follicles regress along the way.

Myths and facts

• Myth: only one egg is lost each month. Fact: usually only one egg ovulates, but many follicles are broken down in the same time period.
• Myth: a good AMH level automatically means good egg quality. Fact: AMH mainly reflects reserve, not the genetic quality of individual eggs.
• Myth: without ovulation, the ovarian reserve stops declining. Fact: age-related follicle loss continues even without ovulation.
• Myth: low reserve means pregnancy is impossible. Fact: pregnancy can still be possible with low reserve. In that situation, a fast and structured assessment is often especially helpful.

Conclusion

The ovarian reserve is finite and declines over time, while most cycles ovulate only one egg. If you need clarity, AMH and antral follicle count are useful estimates that should be interpreted together with age and your personal situation.