Common Causes of Male Infertility and Semen Quality Analysis

What are some common causes of male infertility in clinical practice?

In clinical practice, patients often ask, "Doctor, how is infertility treated?" Actually, it's just...

Like the common term "heart disease," infertility is a general term. Its causes are numerous.

Currently, based on the process of spermatogenesis and maturation, sperm can be roughly divided into three categories: one is pretesticular spermatogenesis.

There are two categories of factors: testicular factors and post-testicular factors. If the pathogenic factors are mainly located in...

"Higher-level departments" can be categorized as pre-testicular factors; if it's a "warehouse" (epididymis and seminal vesicles)...

If the problem lies with the "highway" (vas deferens), it's an issue with the testicles themselves; otherwise, it's a problem with the testicles themselves.

If there is a problem with sperm production, it is clearly a testicular factor.

Most pre-testicular factors are endocrine-related. For example, problems with the pituitary gland or hypothalamus in the brain.

This problem can negatively impact the microcirculation and microenvironment of the testes, leading to spermatogenesis disorders. It encompasses many diseases.

Diseases such as brain tumors and Kallmann syndrome manifest as hormonal abnormalities in patients (e.g., follicle abnormalities).

Symptoms include low levels of luteinizing hormone and stimulant hormone, small testes, and olfactory abnormalities.

The second category is caused by testicular factors. For example, cryptorchidism can affect testicular growth and thus...

Sperm production, and conditions such as orchitis, epididymitis, and some congenital chromosomal abnormalities,

Such as Cranfield syndrome.

The last category is post-testicular factors, which mostly involve problems in the sperm ducts after sperm production.

Problems such as vas deferens obstruction, seminal vesicle inflammation, ejaculatory duct obstruction, and male sexual dysfunction.

Those who cannot have intercourse due to obstruction are all considered to have post-testicular factors.

Therefore, from the perspective of sperm production, infertility can be broadly divided into pre-testicular factors, testicular factors, and so on.

Testicular factors and post-testicular factors. Of course, there are other factors if we break them down further or consider other perspectives.

Classification methods include, for example, infectious factors, endocrine factors, and immune factors.

Currently, pretesticular and testicular factors are the most common, while posttesticular factors account for a smaller proportion.

Not too large. Clinically, this is due to testicular spermatogenesis disorders or poor epididymal function causing spermatogenesis problems.

Decreased sperm count and motility are the most common findings.

Kallmann syndrome: also known as hypogonadotropic hypogonadism with olfactory dysfunction

Syndrome, sexual infantilism-anesthesia syndrome, is a rare congenital disorder.

It can be sporadic or familial, with an incidence rate of approximately 1 in 8000 in males. The cause may be genetic.

Defects in certain genes in the chromosome (such as the KAL gene) can impair the function of the olfactory nerve and gonadotropins.

The neurons that release gonadotropins are all underdeveloped, leading to underdeveloped secondary sexual characteristics and olfactory dysfunction.

Sensory disturbances. The characteristic clinical manifestations of this disease include hypogonadism (micropenis, microtestis).

It is characterized by three main features: testicles, no or low sperm count, olfactory dysfunction, and gonadotropin deficiency.

Klinefelter syndrome: also known as congenital testicular hypoplasia syndrome or primary testicular hypoplasia syndrome.

Orchiopathy is a relatively common sex chromosome abnormality, and also the most common type.

Chromosomal abnormality syndromes that cause male infertility have an incidence rate of approximately 1 in 10 newborn male infants.

1/500. The fundamental defect of this disease is that males have an extra X chromosome (the normal male karyotype should be 46,XY).

Clinical features include small testes, gynecomastia in men, and other abnormalities throughout the body.

Poor hair growth, hypogonadism, and elevated follicle-stimulating hormone levels are symptoms found in the vast majority of patients.

The patient presents with azoospermia.

What should normal semen look like?

Semen quality is closely related to fertility. Analyzing semen quality cannot be based solely on semen characteristics.

A single indicator should not be used as a definitive conclusion; a comprehensive analysis of multiple indicators is necessary. Commonly used methods for assessing semen quality include...

The indicators include the following aspects.

(1) Semen volume: refers to the volume of semen ejaculated in a single ejaculation. The normal volume should be more than 1.5 ml.

Milliliters. More than 8 milliliters is considered excessive; in this case, not only does sperm density decrease, but sperm is also more likely to...

Sperm leakage from the vagina can cause a decrease in the total sperm count, and is commonly seen in patients with seminal vesiculitis. If the total sperm count...

A volume of less than 1.5 ml indicates low semen volume, which can easily lead to infertility.

(2) Color: Normal semen is grayish-white or slightly yellow, and becomes translucent milky white after liquefaction.

The color of the semen may be slightly yellowish in men who have not ejaculated for a long time. If the semen is yellowish-green, it suggests male fertility issues.

There may be inflammation in the reproductive tract or accessory glands (such as prostatitis and seminal vesiculitis). If the semen is red...

(Including bright red, light red, dark red, or soy sauce color), the presence of blood in the semen should raise strong suspicion.

Hematospermia (blood in semen) can be diagnosed if it contains a large number of red blood cells, and it is commonly found in the accessory sex glands and posterior urethra.

It can be seen in patients with inflammation, and occasionally in patients with tuberculosis or tumors.

(3) Liquefaction time: Semen is in a gel-like state when it is first ejaculated, and it will liquefy after a period of time.

The process of semen turning from a coagulated state to a liquid state is called liquefaction. The liquefaction time is the time it takes for newly ejaculated semen to change from a coagulated state to a liquid state.

The time required for the gel to transition to a free-flowing state. At room temperature, a normal semen sample takes approximately 60 minutes.

The semen should liquefy completely within the body. If the semen does not liquefy within 30 minutes of ejaculation, it is considered abnormal.

Liquefaction requires the participation of a series of proteolytic enzymes. If semen does not liquefy or liquefies incompletely, it may...

This inhibits sperm motility, thereby reducing the woman's chances of conceiving.

(4) Viscosity: When a glass rod is touched by the liquefied semen and gently lifted, it will form a viscosity.

Semen strands. If the semen is normal, the length of the semen strands should be less than 2 cm; otherwise, it is considered abnormal.

(5) pH value: Semen is weakly alkaline, with a pH value of 7.2~7.8.

(6) Sperm density (concentration): The normal sperm count should exceed 20 million/ml (or 15 million/ml).

(7) Sperm motility: Previously, the World Health Organization (WHO) based its assessment on sperm motility...

Sperm motility is recommended to be classified into four levels: Level A is characterized by active forward movement and rapid linear motion; Level B...

Grade A is characterized by moderate forward movement; Grade B is characterized by stationary sperm movement; Grade C is characterized by inactive sperm. However...

The WHO's new laboratory manual, however, does not consider sperm motility based on differences in sperm motility.

Speed, simply dividing sperm motility into progressive motility (PR) and non-progressive motility (MP)

Non-progressive motility (NP) and immotility (IM).

(8) Sperm morphology: Abnormal sperm refers to sperm with abnormal morphology. Due to the testing standards...

Changes should be observed; abnormal sperm should account for 30% (according to the fourth edition of "Laboratory Examination and Processing of Human Semen").

According to the fifth edition of the "Laboratory Manual for the Examination and Processing of Human Semen") or 96% (according to the fifth edition of the "Laboratory Manual for the Examination and Processing of Human Semen").

Below. If the abnormality rate exceeds the above standards, it is considered abnormal and is called teratospermia.

It may affect fertility.

Why do different hospitals use different semen quality standards?

my country has consistently adhered to the World Health Organization's recommendations for testing semen quality.

The standard method was developed according to the "Laboratory Manual for the Examination and Processing of Human Semen". This manual...

The standards are constantly being improved and changed. According to the 4th edition of this manual: ① Semen volume ≥ 2 ml; ② pH ≥ 7.2; ③

Sperm density ≥20×10⁶/ml; ④ 60 minutes after ejaculation

Within the sperm, over 50% exhibit progressive motility (i.e., grade A+B) or 25% exhibit rapid progressive motility (grade A).

Those who meet all of the above indicators are considered to have normal semen.

In 2010, the World Health Organization released new guidelines for laboratory procedures in the examination and processing of human semen.

According to the standard (5th edition), a semen analysis is considered acceptable when the following conditions are met.

normal.

Currently, both standards are used in medical institutions in my country, but most institutions tend to favor one.

To apply the new version of the standard.