Cryptozoospermia is one of a male infertility diagnosis characterized by very low sperm concentration in fresh sample. The literature usually determine the cryptozoospermia when describing the sperm concentration lower than 1x106 / ml or lower than 500 000 spermatozoa per ml. 

Defined by World Health Organization (WHO) the cryptozoospermia is the situation that spermatozoa cannot be observed in a fresh semen sample. However, it could be found after an extended centrifugation and following microscopic search. As there is just a small number of spermatozoa present in semen, the semen analysis in general medical lab may be misleading and the semen analysis may be mistakenly presented as zero sperm count. 

In case that semen analysis shows zero sperm count, usually the second seminogram (semen analysis) should be requested. It is beneficial to provide also a sequential ejaculate – to provide 2 samples for analysis. The second sample should be given to the lab approximately one or two hours later after the first one; this may contain some sperm even if the first one doesn’t as it is “fresher”. The semen sample should also undergo the process of centrifugation – the sperm are concentrated and separated from the seminal fluid and rest at the bottom of the tube, in the pellet. The sample is then examined under the microscope. 

Because it is extremely difficult to find and very easy to miss the sperm cells in semen, the condition of cryptozoospermia and the diagnosis itself is commonly confused with complete azoospermia (no presence of spermatozoa in semen) or with extremely severe oligozoospermia (one of the categories of oligozoospermia – low sperm concentration). Whilst the diagnosis of azoospermia may be deceptively presented because of the examination errors during semen analysis, the differentiation of cryptozoospermia and extremely severe oligozoospermia is more difficult. As written before, the cryptozoospermia is defined as that spermatozoa cannot be observed in fresh semen sample but could be found after an extended centrifugation and microscopic search. However, the spermatozoa could be found in part of semen samples directly under the microscopic search, but it could not be counted due to extremely low concentration – this is which may determine the diagnosis of extremely severe oligozoospermia from cryptozoospermia. 

The cause of very low sperm count may be the mechanical obstruction (such as ejaculatory duct obstruction) in the seminal ducts at the some point between the testis and the penis; however the the causes of sperm production problems are most likely located at the testes. 

Patients with cryptozoospermia, as well as extremely severe oligozoospermia and azoospermia are suitable for using intracytoplasmic sperm injection (ICSI) infertility treatment. Even though a man suffers from decrease quantity of sperm in ejaculate, the sperm may be isolated from the semen after the centrifugation process when the sperm is concentrated at the bottom of the tube. If the ejaculate does not contain the suitable sample of sperm (due to immotile sperm or sperm abnormal mophology etc.) for next ICSI treatment, the sperm may be obtained by testicular sperm extraction procedure (TESE). 

Associated diseases


Risk factors

A man should have at least 15 million sperm / ml and at least one third of them should have normal motility. Once in vagina, sperm have to overcome unfavorable condition, enter the cervix and fertilize the egg. They must swim quickly enough to reach the egg as an egg can survive up to 48 hours once released from the ovary (this period days last for 4-5 days).

As the sperm have to go through the passage with unfavorable condition and full of obstacles until they reach the egg, it is necessary to have many more of them in the ejaculate. Insufficient sperm count an inability of the sperm to swim (slow, abnormal or no motility)  decrease the chance to pass the way and thus to conceive naturally during the intercourse. 

In the case of cryptozoospermia the sperm count and motiliy is affected substantialy what prevents natural conception,

However, in some conditions the spermtaogenesis can be supressed temporary (e.g. due to the fewer) and the sperm cvalues can be improved when a new spermatogenesis is restored. Therefore, repeated examinations of the sperm parameters are needed in 2 - 4 months.

There is no mentioned prevention of cryptozoospermia.

Problems to conceive naturally, semen analysis with the result of zero sperm count, pain in testes / scrotum, infection processes, other symptoms determinating other connected diseases.

The acupuncture treatment has shown positive results on sperm count in semen if organic (testicular,  ejaculatory duct obstruction etc.) anomalies are excluded.

At the diagnosis of cryptozoospermia, the surgical therapy is more suitable depending on the origin problem. However, the ART treatment is more recommended.

In case of infection, the antibiotics are used to treat the inflammatory processes. Other medical approaches to treat cryptozoospermia include mostly tamoxifen or hormone therapy.

Surgical therapy
Surgical treatments of ejaculatory duct obstructions, varicocele orcryptorchism may achieve positive results in increasing the sperm count.
Ejaculatory duct obstruction
To treat ejaculatory duct obstruction, the method of Transurethral Resection of the Ejaculatory Ducts (TURED) is used and it has become a standard procedure in this diagnosis. The resection may vary depending on severity of the conditions of the obstruction. It may vary from incising the cyst to relive extrinsic compression on the ducts) to deep resection along the ducts in cases of long post-inflammatory obstruction. Extensive resection of ejaculatory ducts may end by opening ejaculatory ducts into the urethra followed by urinary reflux to the vasa; thus the extensive resection should be under taken with caution.

Varicocele surgery
Varicoceles are abnormally dilated testicular veins in the scrotum. Because of that the testicular function is progressively declined and thus the semen parameters, such as sperm motility, concentration or morphology, may deteriorate. Varicocele repair is the most common operation for the treatment of male infertility.

During the operation, a small incision is made in the abdomen close to the place where testicles originally descended through the abdominal wall. The veins that produce the varicocele are identified and cut. This eliminates the blood flow to the varicocele.

Cryptorchism surgery
Cryptorchism is the failure of one or both of the testes to descend into the scrotum. An improperly developed testis may not leave the abdomen and this it may not produce the hormones and cannot produce the sperm cells.

Surgery treatment of cryptorchism is called orchipex. It is not particularly serious operation and it is usually successful. With the increasing age of patient, the operation may involve more risk to the cells that produce sperm cells.

If conservative medical treatments fail to achieve a full term pregnancy, the physician may suggest the patient undergo in vitro fertilization (IVF). IVF and ART generally start with stimulating the ovaries to increase egg production. Most fertility medications are agents that stimulate the development of follicles in the ovary. Examples are gonadotropins and gonadotropin releasing hormone. After stimulation, the physician surgically extracts one or more eggs from the ovary, and unites them with sperm in a laboratory setting, with the intent of producing one or more embryos. Fertilization takes place outside the body, and the fertilized egg is reinserted into the woman's reproductive tract, in a procedure called embryo transfer.

Intracytoplasmic sperm injection (ICSI) is beneficial in the case of male factor infertility where sperm counts are very low or failed fertilization occurred with previous IVF attempt(s). The ICSI procedure involves a single sperm carefully injected into the center of an egg using a microneedle. With ICSI, only one sperm per egg is needed. Without ICSI, you need between 50,000 and 100,000.

Men who ejaculate no sperm, because of blocked tubes in their testes, or because of a genetic condition that prevents their sperm being released, require some form of surgical sperm retrieval to enable ICSI to take place. In case of cryptozoospermia, testicular sperm obtained by surgical excision (TESE) or percutaneous aspiration (TESA) are used in ICSI treatment. Alternatively, the retrieved sperm can be cryopreserved for use in future sperm injection attempts. If all efforts to extract vital sperm cells fail, then donated ones may be recommended.

Find more about related issues


Assisted reproductive technology ―sourced from Fertilitypedia licensed under CC BY-SA 4.0
Creative Commons License
Except where otherwise noted, content on this site is licensed under a Creative Commons Attribution-ShareAlike 4.0 International License, involving multiple copyrights under different terms listed in the Sources section.