The concept of infertility is defined as a married couple with normal sexual function, without contraception, who have failed to achieve natural conception for more than one year. Male infertility refers to infertility in couples where the male partner is the main cause. Approximately 25% of couples fail to conceive after 1 year of marriage. Male factors account for about 50% of the causes of infertility.
The causes of male infertility are mainly divided into two categories: sexual dysfunction including erectile dysfunction and ejaculatory dysfunction, and abnormal sperm indicators such as oligospermia, weak sperm and teratospermia. Up to 60% to 75% of patients have semen analysis showing oligospermia, weak sperm and teratospermia, but no cause can be found, which we call unexplained male infertility, and physicians are sometimes confused about the causes of infertility.
Abnormal semen parameters are mainly oligospermia (including azoospermia), weak sperm (including dead sperm), and teratospermia. Their common causes are listed below.
I. Causes of low sperm count
1, genetic factors
The most common karyotype abnormality is 47XXY (Creutzfeldt-Jakob syndrome), other 46XX, and chromosomal equilibrium translocation, Roche translocation, etc. Y chromosome microdeletion in azoospermia, the incidence of severe oligospermia is about 10%. ICSI treatment of sperm obtained from semen or testicular biopsies of patients with Creutzfeldt-Jakob syndrome, chimeric Creutzfeldt-Jakob syndrome, and Y-chromosome microdeletions may carry the risk of passing the genetic defect to the next generation.
Congenital vas deficiency is a special type of patient with obstructive azoospermia. Their semen volume is quite large, their pH is acidic, and their unilateral or bilateral vas deferens cannot be palpated on physical examination. The diagnosis of this disease can be made by physical examination. The diagnosis of this disease can be made by physical examination. IVF treatment can be performed by epididymal or testicular sperm extraction. Before IVF treatment, both couples can be screened for CF genes, and if both couples have genetic defects, preimplantation diagnosis can be considered. However, at present, there are no common mutation hotspots of CF gene found in domestic patients with congenital vas deficiency, which makes clinical screening difficult.
2.Congenital factors (cryptorchidism)
Cryptorchidism is the most common congenital reproductive organ disease. At least one testicle is not in the scrotum or the testicle is absent, combined or not with a history of trauma to the testicle. Between 44% and 100% of patients with bilateral cryptorchidism have a lower-than-normal sperm count, and more than half of them are azoospermic. In unilateral cryptorchidism, 20-60% of patients have lower than normal sperm counts. Most patients with unilateral or bilateral cryptorchidism can have children despite their reduced sperm count. If normal fertility is not possible, artificial insemination or IVF will be chosen according to the sperm parameters.
3.Reproductive tract obstruction (obstructive azoospermia)
Obstructive azoospermia caused by obstruction of the reproductive tract is common, such as inflammatory obstruction of the epididymis, after bilateral hiatal hernia in early childhood, after bilateral vasectomy, and obstruction of the ejaculatory duct. Semen examination mainly shows normal semen volume and azoospermia. A normal sized testis with palpable vas deferens and normal range of sex hormone assessment were present. Epididymal puncture reveals motile spermatozoa, and testicular biopsy shows normal spermatogenic function of testicular tissue and visible mature spermatozoa. The clinical program is mainly surgical treatment and IVF treatment.
4.Endocrine factors
Endocrine factors in men are rare, and are commonly seen in idiopathic hypogonadism and hyperprolactinemia, mainly manifesting as non-ejaculation, low ejaculation volume and azoospermia. Treatment for idiopathic hypogonadotropic hypogonadism may include HCG and HMG injections. Once the wife is pregnant, the patient may switch to testosterone replacement. For hyperprolactinemia, pituitary tumor size is chosen for surgery or medications such as bromocriptine or ergocalin. If oligospermia or azoospermia remains after treatment, assisted reproduction techniques should be used.
Second, the causes of decreased sperm vitality
1, genetic factors (cilia immobility syndrome)
Cilia immobility syndrome is an autosomal recessive hereditary disease caused by defects in the structure of the sperm tail cilia, which can cause male infertility in addition to the following diseases: chronic bronchitis, bronchial dilatation, chronic sinusitis, otitis media, visceral retroposition, etc. Semen examination suggests normal range of sperm concentration and sperm morphology, but semen can hardly see forward-moving sperm or even motile sperm.
Survival rate test indicates normal range of sperm survival rate. ICSI treatment is available, and if no motile sperm are seen, HOS can be used to select sperm for ICSI treatment. The disease is an autosomal recessive disorder, if the spouse also carries the causative gene, the offspring will be at risk of inheritance.
2.Incomplete obstruction of ejaculatory ducts
Incomplete ejaculatory duct obstruction is a rare but potentially curable male factor infertility. Sometimes it is accompanied by adult-type polycystic kidney. The semen examination mainly shows low semen volume, severe weak spermatozoa and sometimes dead spermatozoa.
The diagnosis of ejaculatory duct obstruction is based on physical examination, hormone testing, semen analysis, and transrectal ultrasonography. A normal size testicle, palpable vas deferens, and normal range of sex hormones are present, but transrectal ultrasound reveals dilated seminal vesicles, dilated ejaculatory ducts, ejaculatory duct stones, and prostatic cysts. Trans-urethral ejaculatory ductotomy is performed for ejaculatory duct obstruction, and semen quality will improve in about 50-90% of patients.
3. Varicocele
A common male disorder, sometimes associated with ipsilateral testicular growth disorders, disorders and discomfort. Studies have shown that the incidence of this disease is about 11% in adult men and 25% in patients with semen abnormalities. Currently, the main surgical procedures are open high spermatic vein ligation, transinguinal spermatic vein ligation, laparoscopic internal spermatic vein ligation, and microscopic spermatic vein ligation. However, the efficacy of varicocele surgery for oligozoospermia is still debated and does not significantly improve the pregnancy rate, especially in patients with low sperm density.
4. Infection factors (reproductive tract infection)
Reproductive tract infections are a potential and curable cause of male infertility. These include urethritis, prostatitis, orchitis, epididymitis, and so on. However, there is a lack of evidence that these diseases have a negative impact on semen quality and male fertility, especially prostatitis, and the relationship between Mycoplasma solium infection and male infertility is not clear.
Third, the causes of increased sperm malformation rate
1, genetic factors (special types of teratospermia)
Round-headed spermatozoa, characteristic performance: characterized by small and round sperm head and absent acrosome. Incidence: round-headed spermatozoa is very rare, less than 1 in 1,000. The main cause of infertility is the absence of the acrosome, which prevents union with the egg and leads to failure of conception. The success rate of ICSI treatment for round-headed spermatozoa is also very low. Donor sperm treatment is usually used.
Other causes include acinar spermatozoa, large-headed multi-tailed spermatozoa and short-tailed spermatozoa, all of which are thought to be due to genetic factors and usually require sperm donor treatment.
2.Unknown causes
The cause of most teratospermia is still unclear. A high rate of teratology can cause a decrease in the natural pregnancy rate, as well as a decrease in IVF fertilization rate and success rate. In addition to the special types of teratospermia mentioned above, some other teratospermia (teratology rate over 96%), usually mostly due to small sperm apex or head size morphology problems, the impact on ICSI is not clear.
3, environmental and alcohol and tobacco factors
Risk factors for male infertility include certain environmental factors, work factors, lifestyle habits, etc., which may affect sperm production. For example, some studies have found that sperm production may be temporarily affected by exposure of the testicles to gradually increasing temperatures during bathing, or by prolonged driving. Prolonged exposure to heavy metals such as lead, cadmium, mercury; or other substances such as pesticides, herbicides, carbon disulfide can also reduce fertility. Chronic alcohol abuse can affect sperm production and reduce sexual function. Moderate smoking affects sperm quality, and excessive smoking can aggravate pre-existing reproductive disorders or exacerbate the effects of other environmental factors on sperm production.
How is male infertility examined and treated?
1. Your medical history
Clinical requirements of the disease, then the interval between the second semen examination should be three months, semen testing especially weak spermia spermia such as: ① whether there has been a subsequent birth, pregnancy, there has been a spontaneous abortion (embryo stopped developing); ② not pregnant for several years; ③ previous examination and treatment after; ④ other diseases such as diabetes, hypertension history; ⑤ previous medication, surgery history; ⑥ urinary tract infection and sexually transmitted diseases; ⑦ epididymitis, orchitis and testicular trauma; ⑧ other factors.
2.Male physical examination
The main purpose is to check whether there are any abnormalities in the reproductive organs, including the penis, testicular volume, epididymis, vas deferens and spermatic veins, and rectal examination of the prostate.
3.Semen examination
When you have been married for one year, have a normal sex life and have not taken contraceptive measures, you can come to the hospital for semen testing; or men who have a history of cryptorchidism, inflammation of the epididymis, small testicles bilaterally and are worried about environmental factors or medications affecting sperm can also choose semen examination. The most critical indicators of semen examination are sperm count, motility and morphology. The methods and standards for semen examination are usually based on the standards published by the World Health Organization (WHO) in the “Laboratory Manual of Human Semen and Sperm-Cervical Mucus Interaction (5th edition)”.
4.Other tests
(1) Sex hormone test
Patients with azoospermia or low sperm concentration need sex hormone testing to assess testicular function.
(2) Karyotype analysis and Y chromosome microdeletion detection
Sex chromosome and autosome karyotype analysis as well as Y chromosome microdeletion testing should be performed in all men with sperm density below 5-10×106/ml and who are infertile.
(3) Ultrasonography
Doppler ultrasonography can also be used as an alternative method to diagnose varicocele. Scrotal ultrasound should be routinely performed for scrotal masses. In some patients, transrectal ultrasound is required if the semen volume is less than 1.5 ml.
(4) Blood, urine and prostate fluid tests
Blood analysis can help detect certain systemic diseases that may affect fertility. Routine urinalysis is useful for clinical management.
(5) Assessment of partner fertility
For mild to moderate oligozoospermia and critical oligozoospermia it is important to pay attention to the examination and treatment of the spouse.
5. Treatment of oligozoospermia
For oligozoospermia, there is a lack of effective cause-specific treatment and evidence-based medical and surgical measures, and the application of assisted reproductive technology (ART) for the treatment of oligozoospermia has been widely used.
Currently, only endocrine-induced male infertility such as hypogonadotropic hypogonadism and hyperprolactinemia can be effectively treated medically with hCG and hMG for hypogonadotropic hypogonadism and with bromocriptine or carmeglumine for hyperprolactinemia. Some of the weak spermatozoa combined with low semen volume diagnosed as ejaculatory duct obstruction can be treated surgically.
The cause of 60% of cases of oligospermia is unknown, and half of those with a cause do not have a targeted treatment plan. For example, accessory gland infections (mainly prostatitis) are defined as having more than 1 million white blood cells per milliliter of semen, and in the absence of other clinical symptoms, there is no definitive conclusion about its effect on fertility and the use of antibiotic therapy. Varicocele accounts for about 23% of infertile men, however the efficacy of varicocele surgery for oligozoospermia remains debated, and the procedure does not significantly improve pregnancy rates, especially in patients with low sperm density.
Empirical treatments attempting to improve semen quality and increase pregnancy rates are still widely used in clinical practice. For decades, many drugs have been applied to treat unexplained oligospermia, such as androgens, gonadotropins, bromocriptine, antioxidants such as vitamin E, pancreatic kinase, adrenocorticotropic hormone, carnitine; and herbal medicines.
Anti-estrogenic drugs such as tamoxifen alone or in combination with androgens may be effective in some patients with oligozoospermia. α-blockers and mast cell blockers have also been used in unexplained oligozoospermia, but there is still a lack of evidence-based evidence. Chinese medicine is also widely used in clinical practice, but it is necessary to grasp the indications and identify the evidence for its use, and not to abuse kidney tonics.
Due to the lack of targeted and effective treatments, improving the fertility status of the partner has become the first-line treatment option to improve pregnancy rates. It is important to pay attention to the diagnosis and treatment of female infertility factors, especially in patients with mild oligozoospermia. Idiopathic oligozoospermia is recommended to start with intrauterine insemination and if 3-6 cycles fail then in vitro fertilization-embryo transfer with single sperm follicular plasmapheresis.