Low ovarian reserve? Causes and possibilities of getting pregnant

The term low ovarian reserve is used when the number of eggs a woman possesses has decreased and as a result getting pregnant naturally is more difficult.

The most frequent cause of a low egg count is age, since the ovum reserve is gradually depleted as the woman gets older, but it is more accentuated from the age of 35-38.

Once a woman reaches menopause, around the age of 50, the ovarian reserve will be completely exhausted, signalling the end of her reproductive life.

How does the ovarian reserve work?

Before going into detail about the ovarian reserve and the causes of its decline, it is necessary to explain the basic functioning of the ovaries as far as oocyte production is concerned.

At the moment of embryonic development, when the future woman is only a fetus in her mother's womb, the formation of oocytes begins. This period ends before the birth of the woman, and as far as it is known today, it is not possible to prolong it.

This means that the woman is born with a certain number of oocytes (millions of them), and that these must be kept as a great treasure in the ovaries, until the moment they are used when trying for pregnancy.

Decrease of egg count during a woman's life

Apart from this, it is known that women ovulate generally only one oocyte a month on a regular basis. However, few people are aware of the fierce battle of the oocytes, which fight to be ovulated. In general, nature seeks the preservation of the species, trying to ensure that through competition that its processes are the most efficient.

In the case of reproduction, the idea is that in the creation of a new life, the best sperm should come together with the best egg. Everyone knows the race in which millions of sperm participate, in which the best and fastest sperm is the first one to arrive at and penetrate the, making it victorious and involved in the creation of the new baby.

A similar thing happens with oocytes. Dozens of inactive oocytes, in the ovarian reserve, are selected every month (as it was said traditionally, although we now know that  this can be even more frequent), to undergo a process that lasts about 3 months and results in only one of them being ovulated.

Characteristics of the ovarian reserve

The number of oocytes that a woman has at any given time is basically the subtraction between the number of oocytes that the woman had generated before her birth (variable in each person) and the number of oocytes that the woman has used throughout her life to ovulate.

This is the concept of ovarian reserve and, as can be deduced from all that has been explained, it has the following characteristics:

• The ovarian reserve can never increase (as far as we know today). The increases that we sometimes see in the biochemical markers of ovarian reserve do not correspond to real increases in the reserve, but to variations of these parameters and to laboratory technical issues.
• The ovarian reserve will inevitably decrease over time, given that women ovulate throughout their fertile lives, using dozens of oocytes each month.
• Certain external agents can reduce the number of oocytes in a patient (surgeries in which part of the ovary is removed, infections of the ovary, chemotherapy or radiotherapy, etc.). In general, anything that chemically or mechanically damages the ovaries will have the effect of reducing the ovarian reserve.
• The process by which oocytes are selected to compete in the ovulation process is irreversible. If the oocyte is not ovulated, it dies and suffers from what is known as Ovarian follicle atresia.

Graphic illustration of a diminished egg count

In addition, oocyte selection is independent of classical female hormones. This means that this process does not stop in pregnancy or with the taking of contraceptives. It even occurs in girls before puberty.

In other words, hormonal treatments such as contraceptives, in vitro fertilization or egg donation only influence the growth of the oocytes, but not their activation and, therefore, do not affect the ovarian reserve.

Causes of a low egg count

Considering what we have discussed so far, it is easy to conclude that the main reason for the low ovarian reserve or low egg count is the age of the woman.

Furthermore, as time passes, not only the quantity of the eggs decreases but also their quality, which further aggravates the fertility problem. This ovarian aging takes place in a very progressive way, but begins to be more evident from the age of 35.

Nevertheless, there are also young women who suffer from low egg count, albeit less frequently.  In addition to age causing a decrease in ovarian reserve, there are other factors that can cause a low number of eggs cells to be available, such as:

• Premature ovarian failure
• Diseases such as endometriosis, autoimmune disorders, chronic infections, etc.
• Genetic factors that determine a lower oocyte endowment or faster oocyte depletion
• Anti-cancer treatments such as chemotherapy and radiotherapy
• Ovarian surgery to remove cysts, teratomas, etc.
• Unhealthy lifestyle habits: stress, obesity, anorexia, tobacco, etc.
• Environmental pollution

Causes of a low ovarian reserve

If you are young and have a low ovarian reserve, it doesn't necessarily mean that your oocyte quality is affected. Thanks to assisted reproductive treatments, You'll still have a better chance of getting pregnant with your own eggs.

Pregnancy with low ovarian reserve

Most women do not know that they have a reduced ovarian reserve until they try to get pregnant.

If a woman has been having unprotected sexual intercourse for an extended time and hasn´t achieved pregnancy, a fertility study is recommended. This is  where a diagnosis of low ovarian reserve can be seen.

Low ovarian reserve and extended trying to conceive

In this case, and taking into account all the factors of the woman and her partner, several fertility strategies or treatments can be carried out for you to help them finally become parents.

These are discussed below:

In vitro fertilization

In vitro fertilization (IVF) is the technique advised for all women with a compromised ovarian reserve.

Thanks to ovarian stimulation, it is possible to avoid the process of oocyte selection that takes place every month and rescue the oocytes condemned to die. In this way, the woman can develop several ovarian follicles during the cycle and then retrieve all the mature eggs by follicular puncture.

If the ovarian reserve is very limited, it may be necessary to carry out several cycles of oocyte accumulation to increase the chances of success.

If you want to know what this treatment consists of in more detail, we encourage you to continue reading the following post: What is IVF?

Egg donation

In more serious cases, with a practically exhausted ovarian reserve and an advanced maternal age, the recommended treatment would be IVF with egg donation.

Although it can be very hard to come to terms with giving up the idea of passing on your genetic load, egg donation has allowed thousands of women to become mothers.

Furthermore, the success rates of Egg donation are among the highest, as young, high-quality eggs are used. This also makes the emotional toll with this treatment much lower than with IVF.

Benefits and disadvantage egg donation ivf

For more information on this treatment, don't miss this: What is Egg donation?

Fertility preservation

Awareness campaigns on female fertility and delayed motherhood conducted by a multitude of clinics have recently led many women to become interested in the status of their ovarian reserve.

As a result, it is becoming possible to identify cases of diminished ovarian reserve in young women between the ages of 20 and 35. However, it is common that these women are not interested in becoming mothers yet, so it is advisable to preserve their fertility before the ovarian reserve decreases more drastically.

The treatment consists of ovarian stimulation to obtain a multitude of mature oocytes and freeze them in liquid nitrogen for an unlimited time until the woman decides to use them to have a child.

How fertility preservation works

If you would to read more about preserving fertility for the future, please click on this article: Fertility preservation in young women. Recommendations and ideas

Video on low ovarian reserve

Michelle Emblenton, biochemist at inviTRA, talks to us in this video about low ovarian reserve:

The term low ovarian reserve is used to describe when a woman has a reduced number of eggs left and therefore her chances of getting pregnant naturally are decreased. The most frequent cause of a low egg count is actually age.

FAQs from users

What are the main causes of a low ovarian reserve?

The most common cause of a women's low egg count is age. This cause is physiological, unavoidable and increasing, since for socio-cultural reasons women are having children at a later age.

There are many others, either because the patient did not generate enough oocytes in her embryonic stage (genetic causes) or because of damage to the ovary (infection, ovarian torsion, endometriosis, surgery, radio or chemotherapy, etc...). These are more infrequent and usually require specialized centers for diagnosis, being equally irreversible today.

Which hormones indicate low ovarian reserve?

Several hormones are analyzed to study a woman's ovarian reserve, such as FSH, LH, progesterone, etc. However, the marker par excellence of a woman's ovarian reserve is the anti-müllerian hormone or AMH.
Read more

How can I know what my egg count is?

There are several ways to find out the status of a woman's ovarian reserve and whether it is in optimal condition. The most recommendable is to go to a gynecologist specialized in fertility and perform an ultrasound and blood test.

By means of the ultrasound, which should be done at the beginning of the menstrual cycle, an antral follicle count (AFC) can be done. There are also a number of biochemical markers that can be determined by a blood hormone analysis: FSH, antimullerian, B-inhibin, estradiol, etc.

Related Article: Ovarian Reserve Test.

What are the symptoms of a low ovarian reserve?

In principle, there is no sign or symptom that can alert a woman that she has a low ovarian reserve. This can only be discovered by a basic sterility test and altered hormonal results such as a low antimullerian hormone value or a high FSH value.

However, women with early ovarian insufficiency and/or very compromised ovarian reserve may have irregular menstrual cycles, with absent menstruation.

How can I improve my egg count?

A woman's ovarian reserve cannot be improved. Women are born with a finite number of eggs, these are exhausted over the years and, unlike sperm, there is no mechanism for producing new eggs in the ovaries.

However, in order to optimize fertility treatments and obtain a good number of eggs in stimulation, it is advisable to follow healthy lifestyle habits, keep an adequate BMI, follow a healthy and balanced diet, practice sports and avoid toxic substances such as tobacco or alcohol.

Can I improve my AMH levels?

Unfortunately this is not possible. Antimüllerian hormone (AMH) is a good marker of ovarian reserve in women. The values of this hormone indicate the amount of eggs available in a woman at a given time. As time progresses, the ovarian reserve and, therefore, the amount of AMH decreases.

However, leading a healthy lifestyle, taking vitamins, reducing stress, etc. are some tips for women who wish to become mothers.

Recommended reading

One of the consequences of having a low ovarian reserve is not obtaining the desired number of eggs to do an IVF cycle and increase the possibility of pregnancy. If you want to learn more about this and the possible solutions, then please read this post: Low responders in IVF cycles - management and best protocols.

Although it is not always the case, a low ovarian reserve can also be accompanied by poor oocyte quality. To get more information about this, we encourage you to continue reading here: Egg quality in Females - How to achieve high-quality oocytes.