Cryptozoospermia – Definition, Causes, Treatment & Pregnancy

By BSc, MSc (embryologist) and BA, MA (fertility counselor).
Last Update: 04/23/2018

Cryptozoospermia is a severe sperm disorder that is characterized by a very low sperm count. For this reason, it is a common cause of male infertility.

Sperm samples of good quality have the right sperm count, with motile progressive sperm, and normal morphology.

Males with cryptozoospermia are considered to have virtual azoospermia, that is, the number of sperm present in their ejaculate is extremely low. For this reason, the chances for this males to conceive naturally are nearly zero.


Cryptozoospermia is defined as a very low sperm count in the ejaculate. In fact, it is often confused with azoospermia, that is, the total absence of sperm in the ejaculate.

In particular, a man is diagnosed with cryptozoospermia when his sperm count in lower than 100,000 sperm per milliliter.

According to the guidelines published by the World Health Organization (WHO), in order to consider that a man has a normal sperm count, the number of sperm found in the ejaculate should be equal to or higher than 15 million sperm/ml.

Cryptozoospermia is a less common type of oligozoospermia, which refers to low sperm count as well. A sample is diagnosed with oligozoospermia if the total amount of sperm ranges between 100.000 and 15 million sperm/ml. In other words, cryptozoospermia is a severe type of oligospermia, as the sperm count is seriously compromised.

To achieve a pregnancy naturally, in addition to the sperm count, sperm motility and morphology should be normal as well. If not, it would be a case of asthenozoospermia and teratozoospermia, respectively.

One should note that men with cryptozoospermia have only a few sperm in the ejaculate. For this reason, measuring the specific number of sperms that are able to move progressively or have a normal shape is almost impossible.


In order to evaluate the quality of a sperm sample, the most important test to carry out is a semen analysis or seminogram, which allows the sample to be examined both macroscopically and microscopically.

If alterations were found in the different sperm parameters, your doctor may require you to do some additional tests, including a hormonal analysis, physical exploration, and/or even an ultrasound scan. The goal is to gather as much information as possible to find the cause of infertility.

What follows are the most common tests performed to diagnose cryptozoospermia:

Sperm counting chamber

To determine the sperm count of a sperm sample, your doctor will examine the sample under the microscope aided by a counting chamber. Each chamber has a scored-in counting grid to make the sperm counting process easier.

There exist two types of sperm counting chambers nowadays:

Makler chamber
Given that it measures by millions per ml, cases of cryptozoospermia cannot fit into that scale, and therefore it becomes useless. Other types of chambers able to cover reduced amounts of sperm are required.
Neubauer chamber
It allows the specialist to accurately measure values of 10,000 spermatozoa per ml.

When a sperm specimen has cryptozoospermia, it is likely that no sperms or only a few are found under the microscope.

In these cases, the sample is centrifuged to eliminate seminal plasma and make the few sperms that are present to come into contact with the bottom of the conical centrifuge tube (this is called pellet). Then, the bottom of the tube is observed under the microscope in order to see if a sperm layer has formed.

In around 30% of the cases of cryptozoospermia, sperms are found in the sperm sample thanks to this technique.

Hormonal testing

There exist two hormones that play a major role in male fertility. For this reason, monitoring their levels allows us to determine if spermatogenesis (process of sperm production) is taking place normally in the testes, or if there's a prevailing condition preventing it.

We are talking about FSH (follicle-stimulating hormone), released by the pituitary gland to regulate sperm production, and inhibin B, released by the testes once sperm cells are formed.

Here's what FSH and inhibin B levels can tell us about male fertility:

Normal levels of FSH and inhibin B
Spermatogenesis is taking place with normality. It would be a case of obstructive cryptozoospermia.
High FSH and low inhibin B levels
Testicular failure is compromising the sperm production process. It would be a case of non-obstructive cryptozoospermia.
Low FSH and inhibin B levels
The pituitary gland is not working properly, which affects spermatogenesis directly. It would be a case of non-obstructive cryptozoospermia as well.

Based on the type of cryptozoospermia (obstructive or non-obstructive), the treatment to try to increase the sperm count might vary.


Discovering the particular causes of cryptozoospermia is a considerably difficult task. In the majority of cases, the man is unaware that he has this sperm disorder until he starts trying to conceive.

However, the potential causes can be classified into the following groups depending on their origin:

Pre-testicular causes
Those that alter the hormonal regulation of spermatogenesis, including conditions such as hypogonadism, or unhealthy habits (tobacco, alcoholic drinks, environmental toxics, etc.).
Testicular causes
They affect the testicles directly, including cryptorchidism, hydrocele, trauma, varicocele...
Post-testicular causes
They cause obstructive cryptozoospermia, as they prevent the sperms from flowing to the outside world. Examples include ejaculatory duct obstruction, absence of ejaculatory ducts, vasectomy, and urethritis (inflammation of the urethra).

The grade of severity of these causes will determine whether the man is suffering from oligozoospermia, cryptozoospermia, or azoospermia.


The potential solutions to cure cryptozoospermia depend solely on the cause or causes behind it.

Firstly, if it is caused by hormonal imbalances that affect sperm production, a hormone-replacement therapy might work to stimulate sperm production in the testes.

On the other hand, in cases where it is due to a testicular disorder like varicocele, fertility may be recovered through a surgical procedure.

Unfortunately, there's not much natural remedies can do to improve cryptozoospermia. In any case, males with issues with the quality of the sperm they produce should follow healthy lifestyle habits in all cases, including following a balanced diet, with foods that are rich in antioxidants, etc.

Taking Andean root powder is a common advice amongst men with poor sperm quality due to its multiple benefits for male fertility. However, its effectiveness has not been scientifically proven, and unfortunately it won't make natural conception possible in men with cryptozoospermia.

Cryptozoospermia & pregnancy

Men with cryptozoospermia who have been trying to conceive for a long time find it considerably difficult to achieve a natural pregnancy due to their almost non-existent sperm count. The good news is that pregnancy is still possible, yet unlikely, as long as there are a few sperm live in the sperm specimen.

Experts recommend that couples who are trying to have a baby and find themselves in this situation turn to Assisted Reproductive Technology (ART). Particularly, IVF with ICSI (Intracytoplasmic Sperm Injection) is the most appropriate treatment.

With IVF/ICSI, as long as the number of viable sperm equals the number of oocytes able to fertilize, pregnancy is possible. Nonetheless, the higher the number of sperm, the better—this way, it would be possible to examine the sperm morphology and motility before proceeding with ICSI.

A potential complication that may occur when ICSI is the treatment of choice is that the quality of the sperm collected decreases, and no viable sperm is present.

In this case, couples have two possible solutions:

Egg vitrification
In order not to make the woman undergo another cycle of ovarian stimulation, the eggs obtained during the first IVF stimulation cycle are cryopreserved until viable sperms are retrieved.
Testicular biopsy
The doctor tries to retrieve sperm directly from the testis via testicular biopsy, a technique medically known as Testicular Sperm Extraction (TESE).

To prevent this, it is recommended that men with cryptozoospermia store several samples of sperm that contain viable spermatozoa before beginning the IVF cycle. By doing this, it will be possible to turn to the frozen sample in case the semen sample collected on the day of egg retrieval contains zero sperm.

In any case, one should keep in mind that ICSI is the fertility treatment indicated for males with cryptozoospermia.

If you need to undergo IVF to become a mother, we recommend that you generate your Fertility Report now. In 3 simple steps, it will show you a list of clinics that fit your preferences and meet our strict quality criteria. Moreover, you will receive a report via email with useful tips to visit a fertility clinic for the first time.

FAQs from users

What is the difference between cryptozoospermia and azoospermia?

By Zaira Salvador BSc, MSc (embryologist).

It is not unusual that, when seeing that the sperm count is zero, sperm samples are diagnosed with azoospermia instead of cryptozoospermia.

The difference between azoospermia and cryptozoospermia is decisive, since a wrong diagnosis may lead to a testicular biopsy or epididymal sperm aspiration to retrieve sperm when there are viable sperms in the ejaculate, but only a few. The difficulty here is being able to find this few sperm in order not to be mistaken.

To avoid errors and provide the patient with the appropriate diagnosis of cryptozoospermia, the most advisable is to repeat the semen analysis. This time, the semen sample should be examined after having gone through a centrifugation process.

Is cryptozoospermia possible after vasectomy?

By Zaira Salvador BSc, MSc (embryologist).

Yes, it is. When a man undergoes vasectomy, sperms do not vanish immediately from his ejaculate. It requires time, between 3 to 6 months or over, until the sperm count diminishes to zero and no sperm are found in the seminal ducts after various ejaculations. Throughout this timeframe, it is possible for the man to have cryptozoospermia.

If you liked this story, you may want to go through this: Post Vasectomy Semen Analysis – How Many Tests to Confirm Sterility?

Suggested for you

ICSI is the most adequate treatment option for men with cryptozoospermia. To get more information about this technique, read: What Is ICSI or Intracytoplasmic Sperm Injection?

As explained above, cryptozoospermia is considered a severe type of oligospermia, since the sperm count is significantly affected. Read this next to learn more: What Is Oligospermia? – Low Sperm Count Causes & Treatment.

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 Zaira Salvador
Zaira Salvador
BSc, MSc
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
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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