How is the number of sperm analyzed in an ejaculation?

To determine how many sperm are in ejaculation, it is necessary to do a semen analysis. This diagnostic test of male fertility allows assessing if there is a sufficient sperm concentration to achieve a natural pregnancy, in addition to other seminal parameters.

The amount of sperm in the male’s semen is important when it comes to getting pregnant since many die on the way to the egg.

The vagina, the passage through the cervix and the arrival to the fallopian tubes are a biological gymkhana in which many sperm do not reach the destination, so it is essential to start the race with a good sperm concentration.

Below you have an index with the 7 points that we are going to deal with in this article.


Sperm count

When a male obtains a semen sample by a masturbation and collects it in a sterile container, it remains at rest in the laboratory for about 20 minutes to promote the liquefaction of the fluid. This time is necessary for the seminal sample to lose viscosity and become more liquid. In addition, the temperature must be adequate so that sperm motility is not altered.

Next, a drop of semen is taken and placed on a counting chamber so that it can be observed under a microscope.

The most widely used sperm counting chamber is the Makler chamber, which consists of a perfectly defined grid of 10 rows x 10 columns that facilitate counting.

The counting method consists of counting the spermatozoa in every 10 squares, that is, in each row or column. This result must be multiplied by the factor 10 6 / ml (1 million per millilitre) and, finally, the sperm concentration expressed in millions of sperm per ml is obtained.

To make the count more reliable, it is necessary to count several rows or columns of the grid and take an average with all the results obtained. In the same way, there are specialists who prefer to count in two different drops of semen so that the result is closer to reality.

Finally, the sperm concentration obtained is multiplied by the volume of the semen sample to find out the total amount of sperm contained in an ejaculation.

Normal values of sperm in the ejaculate

The normal number of sperm in the ejaculate of a fertile male should be equal to or greater than a concentration of 15 million sperm per millilitre or at least a total concentration of 39 million sperm in the ejaculate.

These parameters have been set by the World Health Organization (WHO) in its last report of 2010 with the aim of unifying the criteria and establishing lower reference limits in all andrology laboratories.

In the past, this lower limit of reference for sperm concentration was 20 million/ml sperm (WHO 1999).

However, male fertility has suffered a general decline in recent times and, in addition, men who have children naturally today have an average of 15 million/ml or more.

Assisted reproduction, like any medical treatment, requires you to trust the professionalism of the doctors and the clinic you choose since obviously, not all are the same.

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Therefore, men who obtain less than 15 million / ml of sperm in their semen analysis will have difficulty in achieving a pregnancy. This sperm alteration is what is known as oligospermia.

The low number of sperm

Oligospermia or oligozoospermia is the low concentration of sperm in the ejaculate, taking into account the 15 million/ml that the WHO considers normal.

There are different degrees of severity of oligospermia depending on the higher or lower sperm count. Therefore, the appropriate reproductive technique to achieve pregnancy will vary in each case:

  1. Mild oligospermia with artificial insemination may be sufficient if the woman has no fertility problems.
  2. Cryptozoospermia It is the most serious case of oligospermia (100,000 sperm/ml) and it will necessarily be necessary to resort to ICSI in order to fertilize the eggs.

The most extreme case would be azoospermia, that is when no sperm is found in the semen. Sometimes it is possible to recover sperm directly from the testicle with a biopsy, but if this is not possible, you would have to resort to a sperm donation to become a father.

Causes of low sperm count

The causes of low sperm count in men are very diverse and sometimes unknown. There are more frequent factors or situations that can cause the alteration of the seminal values in a specific way. Some of them are the following:

  • Some nutritional deficiency.
  • Fever episode in the last three months.
  • Presence of stress.

When these symptoms disappear, normally the sperm concentration returns to its normal values ​​and the man regains his fertility. For this reason, it is essential to repeat second semen analysis after a while trying to lead good life habits and taking care of health.

Questions from users

What is the optimal amount of sperm that a semen sample should have?

When we analyze a semen sample using a semen analysis, we examine several factors, paying particular attention to density (number of sperm per millilitre of ejaculated semen), mobility (number of motile sperm), and pH. Examining the density alone is insufficient to assess whether the sample is adequate or not.

Ideally, all seminal parameters should be the same or above normal. In addition, there must be more than 20 million motile sperm after processing the sample prior to insemination. If all of this is true, then the sample will be considered optimal for IVF.

How many sperm does a man need to be fertile?

According to the reference limits for the analysis of seminal samples established by the WHO, a semen sample is considered normal when it has a minimum of 15 million sperm per millilitre and 39 million sperm in the ejaculate.

It should be said that despite these being the reference values ​​to be able to classify a semen sample as normal, this does not mean that men with semen samples below these values ​​are infertile.

Can you increase the number of sperm?

Yes, as long as the male’s testicles are functional and there is sperm production. There are nutritional supplements that can help improve this sperm production, such as vitamin complexes and antioxidants that reduce the damage that free radicals generate to sperm.

How many sperm do the testicles produce per day?

The testes are capable of producing several million sperm on a daily basis, despite the fact that these take approximately 3 months to generate and mature properly.

The amount varies from man to man so that a fertile man can ejaculate between 15 and 250 million sperm.

How many sperm can an egg fertilize?

An egg can only be fertilized by one sperm. If more than one sperm penetrated the egg, which is known as polyspermia, the embryo would not be viable and would die as it would have an excessive number of chromosomes.

The human being has 46 chromosomes, 23 from the ovum and 23 from the sperm. Therefore, if 2 sperm were to enter an egg there would be 46 chromosomes from the father in addition to the 23 from the mother, which is not compatible with life.

To avoid this, when fertilization by a sperm occurs, the egg activates an internal mechanism that prevents the entry of more sperm. If this mechanism were to fail, the embryo would be unviable and pregnancy would not take place.

How many sperm does it take to get a woman pregnant?

Although it only takes one sperm to fertilize an egg, there need to be millions of them to ensure this is possible. The sperm have to be able to get from the vagina to the fallopian tube where it meets the egg and they will have to overcome many obstacles during the journey.

Therefore, the WHO considers that at least 15 million sperm/ml or 39 million / ejaculate are required to ensure that a natural pregnancy can occur.

Does the number of sperm decrease with age?

There does not seem to be a relationship between the decrease in sperm concentration and age. However, other seminal parameters such as sperm mobility and vitality are altered. This may be due to oxidation of sperm, which decreases their ability to fertilize and increases sperm DNA damage.

The volume of semen also decreases progressively due to the ageing of the seminal vesicles that contribute to the formation of seminal fluid.

How many sperm do I have to have for artificial insemination?

For artificial insemination, it is necessary that there is a REM (mobile sperm count) of at least 3 million, that is, that at least this concentration of sperm moves adequately so as to have options to reach the egg and fertilize it.

On the other hand, for in vitro fertilization or ICSI, a minimum number of sperm is not required, especially for ICSI, since a single sperm is chosen for each egg and is inserted directly into it.

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