Dr. Stacy McBroom
Dr. John Upshaw
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Male Infertility

Overview

Infertility is the inability to conceive (reproduce) after at least one year of unprotected intercourse. Since most people are able to conceive within this time, physicians recommend that couples unable to do so be assessed for fertility problems. In men, hormone disorders, illness, reproductive anatomy trauma and obstruction, and sexual dysfunction can temporarily or permanently affect sperm and prevent conception. Some disorders become more difficult to treat the longer they persist without treatment.

Sperm development (spermatogenesis) takes place in the seminiferous tubules (ducts) of the testes. Cell division produces spermatozoa (mature sperm cells) that contain one-half of a man's genetic code. Each spermatogenesis cycle consists of six stages and takes about 16 days to complete. Approximately five cycles, or 2 months, are needed to produce one mature sperm. Mitochondria (energy-generating organelles) inside each sperm power its tail (flagellum) so that it can swim to the female egg once inside the vagina. Sperm development is ultimately controlled by the endocrine (hormonal) system that comprises the hypothalamic-pituitary-gonadal axis.

Because sperm development takes over 2 months, illness that was present during the first cycle may affect mature sperm, regardless of a man's health at the time of examination.

Incidence and Prevalence
According to the National Institutes of Health, male infertility is involved in approximately 40% of the 2.6 million infertile married couples in the United States. One-half of these men experience irreversible infertility and cannot father children, and a small number of these cases are caused by a treatable medical condition.

Causes and Risk Factors

The primary causes of male infertility are problems with sperm production or delivery. Impaired production or delivery may result from hormonal dysfunction, trauma or defect in the reproductive system, and illness:

  • Cryptorchidism (failure of testes to descend; can impair spermatogenesis)
  • Cystic fibrosis (may cause absence of sperm, vas deferens, or seminal vesicles)
  • Ductal obstruction (caused by repeated infection, inflammation, or developmental defect)
  • Hemochromatosis (metabolic disorder; causes iron deposition in the testes)
  • Hormone dysfunction (caused by disorder in the hypothalamic-pituitary-gonadal axis)
  • Drugs
  • Retrograde ejaculation
  • Sexually transmitted diseases (STDs; cause obstruction, infection, and scarring)
  • Sickle cell anemia (can cause hypogonadism)
  • Systemic disease (fever, infection, kidney disease, metabolic disorder; can impair spermatogenesis)
  • Testicular cancer
  • Testicular trauma (damage to testes)
  • Varicocele

Certain drugs used to treat hypertension, arthritis, and digestive disease, as well as chemotherapy drugs are associated with sperm production problems and infertility.

Retrograde ejaculation occurs when impairment of the muscles or nerves of the bladder neck prohibit it from closing during ejaculation, allowing semen to flow backwards into the bladder. It may result from bladder surgery, a developmental defect in the urethra or bladder, or disease that affects the nervous system, including diabetes. Diminished or "dry" ejaculation and cloudy urine after ejaculation may be signs of this condition.

Inflammatory infections of the prostate (prostatitis), epididymis (epididymitis), and testicles (orchitis), can cause irreversible infertility if they occur before puberty.

Testicular trauma, resulting from injury, surgery, or infection can trigger an immune response in the testes that may damage sperm. Though their effects are not fully understood, antibodies can impair a sperm cell's ability to swim through cervical mucus or to penetrate a female egg.