Male infertility refers to infertility in couples where the male partner is the primary cause. About 25% of couples fail to conceive within 1 year of marriage. The male factor accounts for about 50% of the causes of infertility.
The causes of male infertility are mainly divided into two categories: one is sexual dysfunction including erectile dysfunction, ejaculatory dysfunction; the other is abnormal sperm indicators such as oligospermia, weak sperm and teratospermia. Up to 60-75% of patients have semen analysis showing varying degrees of oligospermia, weak sperm and teratospermia, but some still cannot be identified as the true cause of infertility. For those plausible results, we call them unexplained male infertility, which often confuses even doctors. Let us count the “culprits” of male infertility due to abnormal sperm quality.
A. Causes of low sperm count
1, genetic factors
The most common karyotype abnormality is 47XXY (Creutzfeldt-Jakob syndrome), and there are 46XX, chromosomal balance translocation, Roche translocation, etc. The incidence of Y chromosome microdeletion in patients with azoospermia and severe oligospermia is about 10%.
2.Cryptorchidism
Cryptorchidism is the most common congenital reproductive organ disease. Patients have at least one testicle not in the scrotum or testicular agenesis, 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, more than half of which are azoospermic, and between 20% and 60% of patients with unilateral cryptorchidism have a lower than normal sperm count. Most patients with unilateral or bilateral cryptorchidism can have children despite their reduced sperm count.
3.Obstruction of reproductive tract (obstructive azoospermia)
Obstructive azoospermia caused by obstruction of the reproductive tract is commonly caused by inflammatory obstruction of the epididymis, post-operative bilateral inguinal hernia at an early age, post-operative bilateral vasectomy, and obstruction of the ejaculatory duct. Semen examination mainly shows normal semen volume, but no sperm. Physical examination reveals that the patient possesses normal size testes, palpable vas deferens, and sex hormone test is in the normal range. Epididymal puncture in such patients reveals motile spermatozoa, and testicular biopsy indicates normal spermatogenesis of testicular tissue with mature spermatozoa visible.
Congenital vas deficiency is a special type of patient with obstructive azoospermia. Its semen volume is quite a lot, acidity is acidic, and physical examination cannot palpate unilateral or bilateral vas deferens, the diagnosis of this disease can be made through physical examination.
4.Endocrine factors
Male endocrine factors are relatively rare, clinically common are idiopathic hypogonadotropic hypogonadism and hyperprolactinemia, the main clinical manifestations are non-ejaculation, low ejaculate volume and azoospermia.
Second, the causes of reduced 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 translocation, etc. Semen examination suggests that sperm concentration and sperm morphology are in the normal range, and survival rate test suggests that sperm survival rate is in the normal range, but semen can hardly see forward-moving sperm, or even active sperm, all of which are indiscriminate.
2.Incomplete obstruction of the ejaculatory duct
Ejaculatory duct incomplete obstruction is a rare but potentially curable male factor infertility. Sometimes accompanied by adult-type polycystic kidney. Semen examination mainly shows low semen volume, severe weak sperm and sometimes dead sperm. The diagnosis of ejaculatory duct obstruction is based on physical examination, hormone testing, semen analysis, and transrectal ultrasonography. The patient possesses normal size testes, the vas deferens can be palpated, sex hormones are in the normal range, and transrectal ultrasound can reveal signs such as dilated seminal glands, dilated ejaculatory ducts, ejaculatory duct stones, and prostate cysts.
3.Spermatic varicose vein
Varicocele is a common male disorder, sometimes accompanied by ipsilateral testicular growth disorder and discomfort. Some studies have shown that the incidence of the disease is about 11% in adult men and 25% in patients with semen abnormalities.
4.Infection factors (reproductive tract infection)
Reproductive tract infections are a potentially curable category of diseases that can lead to 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 elevated 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 are 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. Other causes include needle-headed spermatozoa, large-headed multi-tailed spermatozoa, and short-tailed spermatozoa, all of which are currently thought to be caused by genetic factors.
2.Unknown causes
The cause of most teratospermia is still unclear. A high rate of teratology can cause a decrease in natural pregnancy rate, as well as a decrease in fertilization rate and success rate of IVF.
IV. Risk factors for male infertility
Other risk factors for male infertility are certain environmental factors, work factors, and lifestyle habits that may affect sperm production. For example, some studies have found that sauna baths may temporarily affect sperm production due to exposure of the testicles to higher temperatures, or prolonged driving. Prolonged exposure to heavy metals such as lead, cadmium, mercury, or other substances such as pesticides, herbicides, and 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.