Contact us by calling to 938 611 828 or by sending us an email:




Fertility » Causes of male infertility

Causes of male infertility

When a couple is unable to conceive it is necessary to find out the underlying causes of infertility. An accurate diagnosis will allow the specialist to choose the best treatment plan based on the patient´s individual needs and to evaluate the chances of success in each particular case.

The investigations carried out on the couple aim to detect disorders or abnormalities that may lead to infertility and sterility. In 40% of the cases the cause is identified only in the female, in another 40% the cause is identified only in the male and in 20% of cases causes can be detected in both partners. However in 15% of the couples the underlying cause of infertility cannot be detected by the current diagnostic methods. Luckily the percentage of cases with unexplained infertility is decreasing.

Some couples are unable to conceive – i.e. when there is a tubal blockage or an azoospermia) while others just have a lower reproductive function caused by mild abnormalities.

1. OLIGOASTHENOTERATOZOOSPERMIA

Oligozoospermia: semen with a low concentration of sperm. It is generally associated with a low sperm production in the testicles, although it is not infrequent to find a partial vas deferens obstruction.
•    Asthenozoospermia: reduced sperm progressive motility. It can have its origin in the testicles and the epididymis (the sperm becomes motile here). It could be due to the presence of chemicals, infections, immunological processes in the seminal fluid or genetic abnormalities affecting the sperm structure.
•    Teratozoospermia: low percentage of sperm with normal morphology. It can have its origin in the testicles or have a cytogenetical cause. This condition rarely appears alone.

These alterations often appear in combinations, e.g. asthenoteratozoospermia, oligoasthenozoospermia, etc. Oligoasthenoteratozoospermia is the most common alteration on the sperm of infertile men.

The ability of the sperm to fertilize the eggs and achieve a spontaneous pregnancy will depend on the extent of the problem.

Causes of oligoasthenoteratozoospermia:

Testicular failure

Most of oligozoospermias are due to failure of the testicles to make sperm (abnormal spermatogenesis). There are some known factors that may damage the testicles germinal epithelium and reduce the ability to produce sperm: orchitis, trauma, inguinal surgeries, cryptorchidism, chemotherapy, radiotherapy, etc. Sometimes the presence of genetic or chromosomal abnormalities may lead to a poor testicular function, although in most of the cases the cause of a testicular failure is unknown.

Investigations to detect a testicular dysfunction include a blood test to check the FSH and Inhibin B hormone levels. If the blood test does not help to make a diagnosis it is recommended to perform a testicular biopsy to evaluate the extent of the problem and the possibility of treating it with drugs. High FSH levels indicate a testicular disorder without any chances to improve. In these cases it is not possible to use drugs to improve the sperm quality and therefore the only option that may offer higher chances of success is to use assisted conception techniques.

Immunological factor:  in some cases the body does not recognize the own sperm and creates antibodies that attach to the sperm so that they can be detected by the immune system. This may cause the sperm to become immobilized or to clump together affecting its motility and may lead to sperm surface alterations that make it more difficult for sperm to fertilize the eggs.

Hormonal factor: some hormonal disorders, such as the hypogonadotropic hypogonadism, reduce sperm production in the testicles. Treatment involves drugs that help restore normal hormonal levels and recover a good testicle function and a normal sperm production.

Partial blockage: the blockage of one of seminal vesicles results in the semen having sperm cells produced in one single testicle.

Varicocele

Swollen blood vessels around the testicles. A varicocele can be mild, moderate or severe. Varicose veins may cause a rise in testicular temperature or have a toxic effect on the sperm reducing its concentration and motility. The role of a varicocele in male infertility is controversial and greatly varies from one case to the other.

Inflammation or infection

Infections in the testicles, prostate, vas deferens or seminal vesicles may reduce the sperm quality and affect its motility, even if there are no symptoms. Chronic and acute infections can be detected and treated.

Immunological factor

In some cases the body does not recognize the own sperm and creates antibodies that attach to the sperm so that they can be detected by the immune system. This may cause the sperm to become immobilized or to clump together affecting its motility and may lead to sperm surface alterations that make it more difficult for sperm to fertilize the eggs.

Hormonal factor

Some hormonal disorders, such as the hypogonadotropic hypogonadism, reduce sperm production in the testicles. Treatment involves drugs that help restore normal hormonal levels and recover a good testicle function and a normal sperm production.

Partial blockage

The blockage of one of seminal vesicles results in the semen having sperm cells produced in one single testicle.

2. AZOOSPERMIA

Absence of sperm in the ejaculate fluid.

There are two forms of azoospermia:

Obstructive azoospermia

Sperm is created normally but there is an obstruction preventing normal transport of the sperm through the ducts. The obstruction can be caused by an infection, trauma, inguinal surgery, agenesis of vas deferens, prior vasectomy, etc.

Secretory

There is a low or lack of sperm production in the testicles. This is commonly caused by partial or total testicle removal, orchitis, trauma, inguinal surgery, cryptorchidism, genetic abnormalities, chemotherapy, radiotherapy, etc. but most of the times the cause of a testicular failure is unknown. In some cases sperm is produced in some areas of the testicles and it is possible to retrieve it by performing a testicular biopsy and used it for IVF-ICSI.

The reproductive prognosis greatly varies from one form of azoospermia to the other, obstructive azoospermia being the one with better prognosis.

Investigations to determine the type of azoospermia typically include a physical examination, a complete medical history, a sperm analysis and more importantly a blood test to check the FSH and Inhibin B levels as well as a testicular biopsy.

A particular case of azoospermia is the absence of vas deferens (agenesis). In these cases it is important to undertake a cystic fibrosis test. There is evidence that patients who are carriers of one of the cystic fibrosis gene mutations often have agenesis of vas deferens. The cystic fibrosis is the most common autosomal hereditary disease in our population.

The presence of an abnormal karyotype and Y chromosome microdeletion may be genetic causes of secretory azoospermia. These two tests are very helpful to make an accurate diagnosis and offer appropriate genetic counseling when needed.

 

3. ANEJACULATION

The anejaculation refers to the inability to ejaculate.

Retrograde ejaculation is a particular case of anejaculation. It occurs when semen pushes backwards into the bladder instead of out the urethra. In these cases it is possible to collect the sperm present in the urine after having had an orgasm and use it in assisted reproduction techniques.

This condition can be caused by a psychological or neurological disorder (spinal cord injury, diabetes mellitus, etc.) or an obstruction.

 

4. STERILITY DIAGNOSTIC

Spermiogramm

The spermiogramm is a test to analyze the semen which is a fluid containing spermatozoa and seminal plasma.

The sperm analysis checks several physical aspects of the sample such as:

  • Volume
  • PH
  • Liquefaction

Although this, the most important part of the test is the microscopic study. This will give us information on the most relevant parameters of the sample and its fertility potential:

  • Concentration
  • Motility
  • Morphology

The reference values fixed by the World Health Organization to assess the sperm parameters are detailed below:

  • Volume    ≥ 1,5ml
  • Sperm concentration    ≥ 15.000.000 sperms/ml
  • Total number of sperm    ≥ 39.000.000 sperms/ml
  • Motility    ≥ 32% progressive sperm  ≥ 40% mobile sperm
  • Morphology     ≥ 4% normal forms
  • Sperm viability test    ≥ 50% of sperm alive
Sperm preparation

The sperm preparation is a test done on the sperm to determine the number of progressive spermatozoa that can be isolated from an ejaculate specimen and used in assisted conception techniques.

The aim of washing and preparing the sperm is to separate the sperm from the seminal fluid and low motile sperm to obtain only the good motile sperm.

This test allows to evaluate the number of motile sperm collected and decide the most appropriate treatment, taking into consideration whether there is tubal blockage or not. If the total number of progressive sperm is above 3 million the sample will be suitable for artificial insemination. If it is below 3 million IVF will be the most appropriate treatment.

DNA fragmentation

DNA fragmentation is the presence of cuts or loss of material in the spermatozoa’s DNA chains.

DNA fragmentation can affect fertility, because the embryos generated with these spermatozoa are more likely to be of low quality and/or have low potential for implantation.

The study of fragmentation is an independent and complementary parameter vis-a-vis the traditional parameters for measuring potential fertility of sperm (motility, concentration and sperm morphology).

Factors that could cause sperm fragmentation are:

  • Creation of oxygen free radicals or oxidative stress
  • Abnormal chromatin packaging
    • Deficiencies in recombination
    • Apoptosis after the release of the sperm from the tube
    • External causes that can cause or increase the previous factors:
      • Environmental:

Contamination

Smoking

High testicular temperature (fever, tight clothes)

Drugs (such as selective serotonin reuptake inhibitors)

Metabolic changes due to overweight

Age

  • Pathological:

Cryptorchidism

Varicocele

Inflammation or infection of the genital tract

Cancer

Febrile episodes

Stress

 

There are several techniques for the study of fragmentation: TUNEL, SCSA, COMETA, SCD (Sperm Chromatin Dispersion)

When fragmentation values ​​exceed 30% patients’ fertility is seriously compromised.

Approximately 15-20% of infertile patients with normal semen analysis has a high fragmentation.

Patients most likely to have a high sperm DNA fragmentation are:

  • BMI> 25
  • Age (> 45 years)
  • Smokers (> 10 c / day)
  • Alcohol (> 6 units / week)
  • Varicocele
  • Cryptorchidism
  • Severe seminal factor
  • Diabetis mellitus
  • Chemotherapy
  • Previous implantation attempts failed
  • Idiopathic infertility
  • Infertility (≥ 2 abortions)
Testicular biopsy

A testicular biopsy involves a small surgical procedure performed under local anesthesia on an outpatient basis. The whole process takes approximately 15 minutes. A small incision is made in order to obtain a sample of testicular tissue.

This sample will be used to carry out the following procedures:

  • Histopathology examinations: comprehensive assessment of the sperm production in the testicles.
  • Meiosis study: detection of chromosomal abnormalities during the spermatozoa development.
  • In azoospermia detection of spermatozoa in the testicles and possibility of freezing it to us it in an IVF-ICSI cycle.

Testicular biopsies are particularly recommended in azoospermia, oligozoospermia (<10 million of spermatozoa), severe low sperm count with  high risk of chromosomally abnormal spermatozoa, recurrent miscarriage, unexplained infertility or after repeated failed fertility treatments (even if the sperm analysis is normal)

Male genetic testing

In some cases it may be necessary to complete the basic fertility testing with genetic investigations to detect genetic and chromosomal abnormalities that may lead to sterility and infertility.

The development of the intracytoplasmic sperm injection (ICSI) changed the reproductive perspectives of lot of men and stressed the important role that genetic and chromosomal abnormalities play in male sterility or infertility and therefore the need to study them.

Genetic and chromosomal abnormalities may alter sperm production or the seminiferous tubules and hence cause sterility or infertility.

The investigations to determine if there are abnormalities are:

  • Karyotype (see “Karyotype”)
  • Meiosis study (see “Meiosis study”)
  • FISH on sperm (see “FISH on sperm”)
  • Specific examinations such as Y chromosome microdeletion or cystic fibrosis test (CFTR).
FISH on sperm

The FISH test is an accurate technique to evaluate the frequencies of numerical chromosomal abnormalities in a cell.

When carried on sperm the FISH allows us to determine the percentage of diploids (basic chromosome number doubled) and aneuploids (abnormal chromosome number) which can decrease fertility. The main inconvenient of this test is that only a limited number of chromosomes can be analyzed.

The FISH on sperm is particularly recommended in patients with oligo, asteno and/or teratozoospermia, abnormal karyotype or when the meiosis study shows alterations.

Meiosis study

Despite having a normal karyotype, some patients may have chromosomal abnormalities on the sperm (a higher or lower number of chromosomes than it should be) that can produce non-viable embryos in case the eggs are successfully fertilized.

The meiosis study is performed on a sample obtained with a testicular biopsy. The doctor will decide whether he requests this test or not based on the andrologist examination and/or the patient´s medical history.

Karyotype

A karyotype is a test to examine the number and structure of chromosomes in a sample of cells. Each cell must have a total of 46 chromosomes divided into 22 autosome matching pairs and two sex chromosomes. The latter will determine the sex of the baby. The karyotyping is done as a blood test.

Carriers of defective chromosomes often have fertility problems due to a low sperm count or abnormal structural changes of the gametes.

Karyotype tests are strongly recommended in couples with fertility problems, especially in cases of azoospermia, severe oligozoospermia, normozoospermia with recurrent miscarriages and patients using ICSI.

Hormonal check-up

Hormonal blood testing may be used for men to detect a low sperm production in the testicles and determine the source of the problem.

The hormonal testing typically includes the FSH, LH, inhibin-B, LH and testosterone.