Ovarian reserve: what it is, how it is measured, and why it is important.

Each woman, throughout her life, carries within her a precious reserve: the finite number of eggs with which she was born. This heritage, called ovarian reserve, represents one of the central factors of female fertility. Understanding what it means, how it is evaluated, and what implications it may have for motherhood—whether natural or through assisted reproduction—is a fundamental step for any woman who wishes to have a child, today or in the future.

Talking about ovarian reserve is not easy: it can evoke fears, anxieties, and even feelings of guilt. Some women discover that their reserve is lower than expected and experience this news as a definitive closure. Others, on the other hand, cling to unrealistic hopes. The truth lies in the middle: ovarian reserve is a useful indicator, which should be interpreted in the context of personal history, age, and overall health. It is neither a condemnation nor an absolute guarantee.

In this article, we delve into the topic with clarity and sensitivity, offering updated information and simple explanations to help guide you without falling into alarmism or unrealistic expectations.

What is ovarian reserve?

Ovarian reserve indicates the quantity and quality of the eggs present in a woman’s ovaries at a given moment in her life.

Each woman is born with approximately 1-2 million eggs.

By puberty, this number decreases to about 300,000-400,000.

Over the years, month after month, the reserve continues to decline.

A frequently cited figure is that by age 30, about 12% of the original eggs remain, while by age 40, less than 3%. These numbers are not meant to scare, but to explain that fertility is related to a natural physiological process.

In addition to the number, the quality of the eggs also declines with age. This translates to:

• Higher risk of chromosomal abnormalities.

• Lower likelihood of fertilization and embryonic development.

• Increased risk of miscarriage.

Understanding one’s ovarian reserve means having a "thermometer" of fertility, knowing that it is not the only factor at play.

How is ovarian reserve measured?

In recent years, reproductive medicine has developed several tools to assess ovarian reserve. None of these tests, taken in isolation, can predict with certainty whether a woman will be able to have a child, but together they offer a valuable picture.

1. Anti-Müllerian Hormone (AMH).

This is the most commonly used parameter today. AMH is produced by the cells of the ovarian follicles and fairly accurately reflects the number of available eggs.

It can be measured on any day of the cycle.

A low value suggests a reduced reserve, but it does not necessarily mean infertility.

2. Antral Follicle Count (AFC)

This is performed via a transvaginal ultrasound at the beginning of the cycle (between days 2 and 5). The sonographer counts the small visible follicles, which represent the candidates to mature in the following cycles.

3.FSH and Estradiol.

These are measured in the early days of the cycle and help assess ovarian response. Elevated FSH levels, for example, may indicate reduced ovarian sensitivity.

It is important to emphasize that these tests do not indicate whether a woman will be able to conceive naturally. However, they can give an indication of how the ovaries might respond to hormonal stimulation in an assisted reproduction process.

Factors that influence ovarian reserve.

Ovarian reserve does not only depend on age, although it remains the most determining variable. There are other factors that can accelerate or reduce its availability.

• Genetics: Some women are born with a more limited reserve.

• Lifestyle: Smoking, obesity, exposure to toxic substances, and oxidative stress can reduce ovarian reserve.

• Diseases: Endometriosis, polycystic ovary syndrome (with complex dynamics), and surgical interventions on the ovaries.

• Oncological treatments: Chemotherapy and radiation therapy can significantly damage ovarian reserve.

Understanding these factors allows, when possible, the adoption of preventive or monitoring strategies.

Ovarian reserve and assisted reproduction.

When a couple turns to assisted reproduction, the assessment of ovarian reserve becomes crucial.

A good reserve allows for stimulation protocols with more predictable results.

A reduced reserve may make it more difficult to obtain enough eggs, even with intense hormonal stimulation.

Some scenarios include:

• Oocyte cryopreservation: Recommended for young women who, although not seeking pregnancy immediately, want to preserve their future possibilities.

• Personalized protocols: Stimulation is adapted on a case-by-case basis to get the most out of a limited reserve.

• Egg donation: When the reserve is very low or the egg quality is compromised, donation becomes a concrete option with high success rates. In Spain, this practice is regulated by clear and well-established regulations.

It is important to say this honestly: a very low ovarian reserve can be an almost definitive obstacle. But at the same time, for many women, the paths of reproductive medicine offer real and concrete solutions.

Spain as a benchmark.

In the last twenty years, Spain has become a global center of excellence for assisted fertility. The reasons are several:

• Law 14/2006: One of the most complete and advanced regulations in Europe.

• Wide availability of egg donors, which ensures reduced waiting times.

• Specialized centers that treat thousands of complex cases each year, with personalized protocols and cutting-edge techniques.

For all these reasons, more and more patients from across Europe choose Spain not only for its scientific possibilities, but also for the welcoming atmosphere and human support they find.

How can Mater Clinic help you?

At Mater Clinic, we believe that knowledge is the first step toward making informed decisions.

That’s why we offer free online consultations, with no obligation, dedicated to all women and couples who wish to better understand their ovarian reserve and evaluate assisted fertility opportunities in Spain.

Our approach is based on three pillars:

1.Clear information: We explain in a simple and scientifically accurate way what the tests and results mean.

2. Personalized guidance: Each story is different, so we propose tailored paths, taking into account age, medical history, and expectations.

3. Empathetic support: Not just medical data, but also listening and support, because we know that behind every question lies a deep desire.

Our goal is to accompany, not replace decisions: to provide tools to choose consciously, without haste or pressure.

Conclusion.

Ovarian reserve is a window into female reproductive potential, but it does not tell the whole story. It is a useful parameter that can guide important decisions, but it should always be interpreted in light of other factors.

A reduced reserve can represent a challenge, sometimes a difficult obstacle to overcome. But it can also be a warning sign that encourages getting informed, not delaying, and exploring the possibilities that reproductive medicine offers today.

In any case, what matters is not to see this issue as a sentence, but as a tool for knowledge. Because motherhood—whether natural or assisted—is not only measured in numbers but in the ability to face one’s own path with realism, hope, and the right support.

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Contacts.

Would you like to assess your ovarian reserve and discover the possibilities offered by assisted fertility in Spain? Book a free online consultation, with no obligation, with the Mater Clinic team:

📱 WhatsApp: 645 096 548

📧 Email: care@mater.clinic

🌐 Website: www.mater.clinic | ginecologia.mater.clinic

Sources.

ESHRE – Ovarian reserve testing and management (Linee guida, 2023).

Human Reproduction Update – Dati sul declino fisiologico della riserva ovarica.

Legge 14/2006 (Spagna) – Normativa sulle tecniche di riproduzione assistita.