1. Endocrine factors: hypogonadism caused by primary gonadotropin deficiency, hypogonadism caused by secondary gonadotropin deficiency, oligospermia caused by high follicle stimulating hormone, hyperprolactinemia, chronic adrenal cortical hypofunction, adrenal cortical hyperplasia, thyroid gland disease, diabetes, etc.
2. Infectious factors: chronic epididymitis, chronic prostatitis, seminal vesiculitis, and specific infections.
3. Varicocele: Due to the increase in local temperature of the testes, it affects the spermatogenic function and sperm motility of the testes.
4. Genetic factors: abnormal somatic cell karyotype and Y chromosome microdeletion are one of the common reasons for spermatogenesis disorders.
5. Immune factors: The male blood-testis barrier is disrupted, producing anti sperm antibodies.
6. Cryptorchidism: If the cryptorchidism is not treated early, oligospermia or azoospermia may occur.
7. Vaginal effusion: Whether it is primary or secondary, it can cause spermatogenic disorders and oligospermia due to increased local temperature in the testicles.
8. Nutritional factors: The lack of nutrients such as amino acids, folic acid, vitamin A, E, and trace elements such as zinc required for spermatogenesis can lead to decreased spermatogenic function.
9. Medications: Some drugs can cause temporary or permanent damage to sperm production, such as large amounts of corticosteroids, androgens, gonadotropin-releasing hormones, reserpine, furans, cimetidine, nitrosamine, spironolactone, colchicine, and some antibiotics, as well as some alkyl compounds in cancer chemotherapy drugs.
10. Environmental factors: long-term exposure to pesticides and chemicals, some organic solvents and heavy metals, drugs, radiation and high temperature can lead to low spermatogenic function, resulting in oligospermia or azoospermia.
11. Chronic disease: Infertility patients with oligospermia caused by renal dysfunction, mainly due to dysfunction of the hypothalamic pituitary gonadal axis, may experience varying degrees of gonadal dysfunction.
12. Other factors: Long term addiction to tobacco and alcohol, frequent wearing of tight pants, and frequent bathing in saunas can all cause oligospermia.