Male infertility has become a significant factor in current infertility cases, largely attributable to modern environmental conditions and dietary habits. What are the common causes of male infertility? What tests are required for diagnosis?
Male Infertility Differentiation
Sexual Dysfunction-Related Infertility
Refers to infertility resulting from sexual dysfunction preventing intercourse completion or sperm entry into the vagina.Patients often have a history of sexual dysfunction such as erectile dysfunction, anejaculation, or retrograde ejaculation, which can be identified through sexual function testing.
(1) Anejaculation:
Refers to normal penile erection but inability to ejaculate during intercourse. It is classified into functional anejaculation and organic anejaculation.The former is often caused by lack of sexual knowledge or psychological factors like nervousness during newlywed periods or excessive sexual activity. The latter commonly results from neurological disorders or injuries (e.g., pelvic surgery), penile conditions (e.g., phimosis or paraphimosis), endocrine diseases (e.g., neuropathy due to pituitary, gonadal, or thyroid insufficiency), or medication effects (e.g., sedatives or adrenergic receptor blockers inhibiting ejaculation).(2) Retrograde Ejaculation: Refers to the sensation of ejaculation during intercourse without semen being expelled through the urethra. Immediate urination after ejaculation reveals a significant presence of sperm in the urine. Common causes include incomplete closure of the bladder neck, pelvic surgery, transurethral resection of the prostate, or urethral strictures hindering semen passage.
Infertility due to obstructive lesions of the spermatic ducts
Spermatogenesis in the testes is normal, but sperm cannot enter the semen due to obstruction of the ducts.Differential diagnosis includes:
(1) Congenital spermatic duct obstruction:
Primarily caused by congenital underdevelopment or absence of the vas deferens, seminal vesicle hypoplasia, failure of vas deferens to connect with the epididymis, or epididymal hypoplasia. Characterized by low semen volume (often <1ml), failure of semen to coagulate, absence of fructose in seminal plasma, and azoospermia.
(2) Infectious Obstruction of the Seminal Ducts:
Common infections include bilateral epididymal tuberculosis, gonococcal epididymitis, and filariasis. Characterized by azoospermia with normal testicular size.
(3) Iatrogenic Obstruction:
Patients often have a history of vas deferens angiography or vasectomy. Bilateral inguinal hernia repair may accidentally ligate the vas deferens, causing obstruction. Damage to the epididymis or spermatic cord during testicular or epididymal surgery can also result in obstruction.
(4) Traumatic Obstruction of the Spermatic Duct:
Azoospermia resulting from obstruction of the spermatic duct following trauma to the testis, epididymis, or spermatic cord.
Infertility Due to Testicular Spermatogenic Dysfunction
This occurs when the testis fails to produce sperm for various reasons. Although the spermatic ducts are normal, no sperm are present in the semen.Differential diagnosis includes:
(1) Genetic abnormalities:
Such as intersex conditions or Klinefelter syndrome, resulting from chromosomal nondisjunction during meiosis creating mosaicism. Clinical features include gynecomastia, sparse facial/pubic hair, narrow shoulders and wide hips (feminine physique); small, soft testes, low libido, and azoospermia.Elevated FSH levels in plasma and urine, with plasma testosterone concentrations below normal.
(2) Congenital abnormalities:
Such as congenital anorchism, bilateral cryptorchidism, and gonadal dysgenesis. In gonadal dysgenesis, virilization is normal but semen is azoospermic. Testes are normal in size, breasts do not enlarge, plasma testosterone and serum LH levels are normal, and plasma FSH is elevated.Patients with bilateral cryptorchidism also exhibit azoospermia, but their testes are non-palpable. Plasma testosterone and serum LH levels are low, yet plasma testosterone levels significantly increase after a single injection of 5000 U chorionic gonadotropin.In congenital anorchism, besides undetectable testes, both plasma testosterone and serum LH levels are markedly low. Plasma testosterone shows only a slight increase after a single injection of chorionic gonadotropin.
(3) Endocrine Abnormalities:
Such as hypogonadism, hypopituitarism, hypothyroidism, and adrenal cortical hyperplasia. Patients with primary hypogonadism often exhibit elevated serum FSH and LH levels, accompanied by reduced testosterone levels.Pituitary insufficiency can cause secondary hypogonadism, where patients exhibit low serum FSH and LH levels, impaired Leydig cell function, diminished sexual function, and reduced semen volume.
(4) Spermatogenic Cell Maturation Disorders:
Such as radiation damage, drug effects, varicocele, etc. Testicular size and texture appear normal, but semen analysis reveals reduced sperm count or azoospermia.Testicular biopsy reveals that the spermatogenic process is often arrested at the spermatocyte stage, with very few spermatids undergoing further development in the seminiferous tubules. Immune infertility Immune infertility is divided into two categories: one is male-produced anti-sperm autoimmunity, and the other is female-produced anti-sperm alloimmunity. The characteristic of these patients is that their sexual function, semen analysis, and hormone levels are all normal.
Male infertility has complex etiologies and can be classified into azoospermia, severe oligospermia, oligospermia, normal sperm count infertility, polyzoospermia, and asthenospermia. Male infertility has complex etiologies and can be classified into azoospermia, severe oligospermia, oligospermia, normal sperm count infertility, polyzoospermia, and asthenospermia.What diagnostic analyses are required for male infertility?
What tests are necessary to confirm male infertility?
Semen analysis
In vitro heterologous fertilization test: This test provides a more accurate assessment of sperm fertilization capacity and is highly valuable for evaluating male fertility. The most common method involves heterologous fertilization of hamster eggs with human sperm, using sperm from fertile males as a control.
Prostate fluid examination
Endocrine testing: Gonadotropin-releasing hormone or clomiphene stimulation tests assess hypothalamic-pituitary-testicular axis function. Testosterone level measurement directly reflects Leydig cell function. Thyroid hormones, adrenocortical hormones, or prolactin may be measured if necessary.
Doppler ultrasound examination.Aids in confirming varicocele.
Radiographic studies. To identify obstruction sites in the spermatic ducts, vas deferens and epididymis angiography, vas deferens and seminal vesicle angiography, or urethral angiography may be employed. For patients with hyperprolactinemia, an X-ray tomogram of the sella turcica (anterior and lateral views) is indicated to rule out pituitary adenoma.
Immunological testing.Sperm agglutination or immobilization assays detect agglutination or immobilization antibodies in serum or seminal plasma. Multiple detection methods exist; selection should be based on local availability.
Testicular biopsy. Used for azoospermia or oligospermia to directly examine spermatogenic function in seminiferous tubules and interstitial cell development. Local hormone synthesis and metabolism can be reflected via immunohistochemical staining.
Chromosome Karyotype Analysis. Used for external genitalia abnormalities, testicular hypoplasia, and idiopathic azoospermia. Important Note: As outlined above, diagnosing male infertility involves identifying the root cause to address issues like reduced sperm count, low motility, or poor survival rates. The most critical step is obtaining a definitive diagnosis followed by consistent treatment as prescribed by a physician.