What Are Antisperm Antibodies? – Causes & Treatment

By (embryologist) and (fertility counselor).
Last Update: 11/05/2018

The presence of antisperm antibodies (ASA) in the ejaculate is an immune cause of male infertility.

The adhesion of antibodies to sperm affects their motility, making the sperm's journey to the egg highly difficult or even impossible.

There exist some treatment options to become a father in spite of having ASA in the semen. Some of them include the use of Assisted Reproductive Technology (ART).

What are antisperm antibodies?

An antibody, also known as immunoglobulin, is a substance produced by the immune system that identifies and attacks strange substances.

There are five types of immunoglobulins depending on the characteristics of each. Particularly, antisperm antibodies belong to types IgA and IgG.

ASA adhere to spermatozoa because they are powerful antigens. Thus, the body of the male identifies them as invaders.

In normal conditions, sperms can be found within the testes, protected from the rest of the body thanks to the so-called blood-testis barrier, where access to antibodies is not possible.

Risk factors

If the blood-testis barrier broke down, ASA would reach the testicles and adhere to spermatozoa right after detecting antigens IgA and IgG on their surface.

Moreover, in some cases it is the female's body which detects spermatozoa as invaders. In this case, antisperm antibodies show up after intercourse.

Simply put, the risk factors for the appearance of ASA vary depending on whether they are present in the body of the male or the female.

These are the situations that may cause damage to the blood-testis barrier:

Although only a minority of women produce antisperm antibodies, two main risk factors can be found:

  • Gynecological infections
  • Female genital tract inflammation

ASA hinder progressive motility of spermatozoa, and interfere in their journey towards the egg cell.


This type of immune infertility can be detected using different techniques that detect the presence of ASA in biological fluids.

More specifically, the presence of ASA can be determined by examining the sperm (direct tests). Also, they can be determined by examining the seminal plasma or the cervical mucus in the woman (indirect tests).

The following are the most common direct tests, which are used to confirm that ASA are adhered to spermatozoa, and therefore the ones used:

SpermMar test

It mixes the semen with small latex particles previously treated with specific antibodies that detect the IgA antisperm antibodies. When these particles interact with ASA, sperm agglutination can be observed under the microscope.

Reference values according to the World Health Organization (WHO) to interpret the results of SpermMar tests are:

  • <10% of sperm adhered: negative result.
  • 10-50% of sperm adhered: questionable diagnosis.
  • >50% of sperm adhered: positive result for ASA.

The SpermMar test IgG kit is a simple test that is performed at Andrology labs on a regular basis.

Immunobeads screen

This is a specific test used to detect two different types of antisperm antibodies: IgG and IgA.

It uses microscopic polyacrylamide spheres covered with ASA specific antiglobulins. This is a more comprehensive screening test than the SpermMar test IgG kit, since it provides information on the particular location of the ASA in sperm (head or tail). However, it is more technically challenging and requires more time.

The result is positive when the value is above 20 percent.

Considering seeing a fertility specialist? Don't forget that, in the field of Reproductive Medicine, as in any other medical area, it is crucial that patients rely on the doctors and staff that will help them through their treatment cycle. Logically, conditions vary from clinic to clinic. For this reason, we recommend that you generate your Fertility Report now. It will offer you a list of clinics that have passed our rigorous selection process successfully. Furthermore, the system will make a comparison between the fees and conditions of each clinic so that you can make a better-informed decision.

Treatment & fertility

When a semen analysis, along with other additional tests, indicate that there exists immune infertility due to the presence of antisperm antibodies, treating it is required to achieve a successful pregnancy.

In principie, removing ASA permanently is not possible, but there exist various treatment options that may help.

What follows are the two main treatment options available for these men to be able to conceive, all of them based on the use of reproductive technologies:

Immunosuppressive therapy using corticosteroids

High doses of corticosteroids can help diminish the amount of antisperm antibodies, and restore male fertility temporarily, thereby increasing the chances of pregnancy during a particular time frame.

Corticosteroids are a type of hormones produced in the suprarenal glands, and have an anti-inflammatory and immunosuppressive effect.

Nevertheless, their effectiveness has not been proven in all patients. Additionally, high doses of corticosteroids can have several side effects, including cardiovascular risks.

Sperm washing & IUI

In case a man has to turn to assisted conception to have a baby, a sperm washing before Artificial Insemination (AI) or In Vitro Fertilization (IVF) helps to diminish the number of ASA in the sperm sample.

A sperm washing, however, has two main drawbacks: 1) it is not 100% effective due to high affinity between ASA and sperm antigens; and 2) it affects sperm motility.

As for AI, these patients may be referred to any of the following types, based on the location of the ASA:

Intrauterine Insemination (IUI)
Antisperm antibodies are present in the cervical mucus. So, given that IUI places the sperm directly into the uterus, it helps to overcome the cervical barrier.
Intratubal Insemination (ITI)
Used when antisperm antibodies are located in the semen due to damage to the blood-testis barrier. For this reason, it is necessary to place the sperms closer to the egg in order for it to be able to hit it. This type of AI is falling into disuse nowadays, though.

Artificial insemination is an effective technique to achieve pregnancy. Unfortunately, when antisperm antibodies are found in the head of sperm, fertilization is unlikely. Conversely, this would not happen if ASA are located in the tail.

Although turning to IVF is another option, the pregnancy rates do not increase, since identifying the sperms that are free of ASA and able fertilize the egg is not possible.

FAQs from users

Can vasectomy reversal induce the production of antisperm antibodies?

By Zaira Salvador B.Sc., M.Sc. (embryologist).

In fact, this is a common cause leading to the appearance of antisperm antibodies (ASA) in the semen. Whilst the vasa deferentia were sealed after a vasectomy, pressure caused by sperm can cause the blood-testis barrier to break down. As a result, sperms are exposed to the immune system, leading to the production of ASA:

What kills sperm in the female body?

By Zaira Salvador B.Sc., M.Sc. (embryologist).

Women can also produce antisperm antibodies that kill sperm right after having unprotected sexual intercourse. The cause are infections of the reproductive tract. It should be noted that, in order to diagnose this type of immune infertility, a series of diagnostic tests to evaluate the cervical mucus are required.

If the result of a SpermMar test is above 50%, does it mean I have antisperm antibodies?

By Zaira Salvador B.Sc., M.Sc. (embryologist).

This result indicates that half the sperm present in the ejaculate are agglutinated, that is, adhered to the latex particles. In other words, the answer is yes: there are antisperm antibodies.

Suggested for you

Throughout this post, we have made several references to Intrauterine Insemination (IUI) being the most adequate technique for patients with ASA. To learn more, we recommend that you click here: What Is Artificial Insemination (AI)? – Process, Cost & Types.

There exist two types of immune infertility aside from antisperm antibodies. To learn more about this, read: What Is Immune Infertility? – Treatment & Pregnancy Options.

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FAQs from users: 'Can vasectomy reversal induce the production of antisperm antibodies?', 'What kills sperm in the female body?' and 'If the result of a SpermMar test is above 50%, does it mean I have antisperm antibodies?'.

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 Zaira Salvador
Zaira Salvador
B.Sc., M.Sc.
Bachelor's Degree in Biotechnology from the Technical University of Valencia (UPV). Biotechnology Degree from the National University of Ireland en Galway (NUIG) and embryologist specializing in Assisted Reproduction, with a Master's Degree in Biotechnology of Human Reproduction from the University of Valencia (UV) and the Valencian Infertility Institute (IVI) More information about Zaira Salvador
License: 3185-CV
Adapted into english by:
 Sandra Fernández
Sandra Fernández
B.A., M.A.
Fertility Counselor
Bachelor of Arts in Translation and Interpreting (English, Spanish, Catalan, German) from the University of Valencia (UV) and Heriot-Watt University, Riccarton Campus (Edinburgh, UK). Postgraduate Course in Legal Translation from the University of Valencia. Specialist in Medical Translation, with several years of experience in the field of Assisted Reproduction. More information about Sandra Fernández

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