Causes and Risk Factors for Male Infertility
Common causes for male infertility include sperm disordersimpaired sperm production or delivery, abnormal sperm development or shape, etc.testosterone deficiency (hypogonadism), and certain medical conditions.
Infertility can result from a condition that is present at birth (congenital) or can develop later (acquired). Causes for infertility include the following:
- Defect or obstruction in the reproductive system (e.g., cryptorchidism, anorchism)
- Disease (e.g., cystic fibrosis, sickle cell anemia, sexually transmitted disease [STD])
- Hormone dysfunction (caused by disorder in the hypothalamic-pituitary-gonadal axis)
- Infection (e.g., prostatitis, epididymitis, orchitis)
- Injury (e.g., testicular trauma)
- Medications (e.g., to treat high blood pressure, arthritis, etc.)
- Metabolic disorders such as hemochromatosis (affects how the body uses and stores iron)
- Retrograde ejaculation (i.e., condition in which semen flows backwards into the bladder during ejaculation)
- Systemic disease (e.g., high fever, infection, kidney disease)
- Testicular cancer
Retrograde ejaculation occurs when impairment of the muscles or nerves of the bladder neck prohibit it from closing during ejaculation. It may result from bladder surgery, a congenital defect in the urethra or bladder, or disease that affects the nervous system. Diminished or "dry" ejaculation and cloudy urine after ejaculation may be signs of this condition.
Hypogonadism may be present at birth (congenital) or may develop later (acquired). Causes of the condition are classified according to their location along the hypothalamic-pituitary-gonadal axis:
- Primary, disruption in the testicles
- Secondary, disruption in the pituitary gland
- Tertiary, disruption in the hypothalamus
The most common congenital cause is Klinefelter syndrome. This condition, which is caused by an extra X chromosome, results in infertility, sparse facial and body hair, abnormal breast enlargement (gynecomastia), and smaller than normal testes.
Congenital hormonal disorders such as leutenizing hormone-releasing hormone (LHRH) deficiency and gonadotropin-releasing hormone (GnRH) deficiency (e.g., Kallmann syndrome) also may cause testosterone deficiency.
Other congenital causes include absence of the testes (anorchism; may also be acquired) and failure of testicles to descend into scrotum (cryptorchidism).
Acquired causes for testosterone deficiency include the following:
- Damage to the pituitary gland, hypothalamus, or testes
- Glandular malformation
- Head trauma affecting the hypothalamus
- Infection (e.g., meningitis, syphilis, mumps)
- Isolated LH deficiency (e.g., fertile eunuch syndrome)
- Testicular trauma
- Tumors of the pituitary gland, hypothalamus, or testicles