Male factors represent the sole factor of infertility in approximately 20% of infertile couples but may contribute to infertility in up to 30-40% of cases. Causes of male-factor infertility include varicoceles, thyroid or other hormonal imbalances, genetic factors, medications, problems with erection or ejaculation, history of pelvic infection or surgery, history of undescended testes, smoking or other drug use, and other causes. Male factor infertility can be defined by abnormal semen analysis parameters but may also be present even when the semen analysis is normal.
What is the goal of a male fertility evaluation?
- Identification and correction of treatable conditions.
- Detection of genetic causes of male infertility in order to understand risk for transmitting genetic abnormalities.
- Determining appropriate treatment options.
What is involved in a male fertility evaluation?
- Discussion of your history with your physician- including any past conceptions, medications, surgeries, or infections.
- Semen analysis: collection of sperm after 48-72 hours of abstinence for evaluation of sperm number, motility, morphology, and other characteristics.
- Physical exam or consultation with a Urologist if indicated.
What does the male component of fertility include?
- You must produce healthy sperm. Initially, this involves the growth and formation of the male reproductive organs during puberty. At least one of your testicles must be functioning correctly, and your body must produce testosterone and other hormones to trigger and maintain sperm production.
- Sperm have to be carried into the semen. Once sperm are produced in the testicles, delicate tubes transport them until they mix with semen and are ejaculated out of the penis.
- There needs to be enough sperm in the semen. If the number of sperm in your semen (sperm count) is low, it decreases the odds that one of your sperm will fertilize your partner’s egg. A low sperm count is fewer than 15 million sperm per milliliter of semen or fewer than 39 million per ejaculate.
- Sperm must be functional and able to move. If the movement (motility) or function of your sperm is abnormal, the sperm may not be able to reach or penetrate your partner’s egg.
What are the causes of male factor infertility?
- Varicocele. A varicocele is a swelling of the veins that drain the testicle. It’s the most common reversible cause of male infertility. This may prevent normal cooling of the testicle, leading to reduced sperm count and fewer moving sperm. In some cases, treating the varicocele may be an option to attempt to improve sperm numbers and function. This may potentially improve outcomes when using assisted reproductive techniques such as in vitro fertilization.
- Infection. Some infections can interfere with sperm production or sperm health, or can cause scarring that blocks the passage of sperm. These include some sexually transmitted infections, including chlamydia and gonorrhea; inflammation of the prostate (prostatitis); and inflamed testicles due to mumps (mumps orchitis). Although some infections can result in permanent testicular damage, most often sperm can still be retrieved.
- Ejaculation issues. Retrograde ejaculation occurs when semen enters the bladder during orgasm instead of emerging out the tip of the penis. Various health conditions can cause retrograde ejaculation, including diabetes, spinal injuries, medications, and surgery of the bladder, prostate or urethra. Some men with spinal cord injuries or certain diseases can’t ejaculate semen, even though they still produce sperm. Often in these cases sperm can still be retrieved for use in assisted reproductive techniques.
- Antibodies that attack sperm. Anti-sperm antibodies are immune system cells that mistakenly identify sperm as harmful invaders and attempt to eliminate them. These may be present if you have had previous testicular surgery or vasectomy.
- Tumors. Cancers and nonmalignant tumors can affect the male reproductive organs directly or can affect the glands that release hormones related to reproduction, such as the pituitary gland. In some cases, surgery, radiation or chemotherapy to treat tumors can affect male fertility.
- Undescended testicles. In some males, during fetal development one or both testicles fail to descend from the abdomen into the sac that normally contains the testicles (scrotum). Decreased fertility is more likely in men who have had this condition.
- Hormone imbalances. Infertility can result from disorders of the testicles themselves or an abnormality affecting other hormonal systems including the hypothalamus, pituitary, thyroid and adrenal glands. Low testosterone (male hypogonadism) and other hormonal problems have a number of possible underlying causes.
- Sperm duct defects. The tubes that carry sperm (sperm ducts) can be damaged by illness or injury. Some men experience blockage in the part of the testicle that stores sperm (epididymis) or a blockage of one or both of the tubes that carry sperm out of the testicles. Men with cystic fibrosis and some other inherited conditions may be born without sperm ducts altogether.
- Chromosome defects. Inherited disorders such as Klinefelter’s syndrome — in which a male is born with two X chromosomes and one Y chromosome (instead of one X and one Y) — cause abnormal development of the male reproductive organs. Other genetic syndromes associated with infertility include cystic fibrosis, Kallmann’s syndrome and Kartagener syndrome.
- Problems with sexual intercourse. These can include trouble keeping or maintaining an erection sufficient for sex (erectile dysfunction), premature ejaculation, painful intercourse, anatomical abnormalities such as having a urethral opening beneath the penis (hypospadias), or psychological or relationship problems that interfere with sex.
- Certain medications. Testosterone replacement therapy, long-term anabolic steroid use, cancer medications (chemotherapy), certain antifungal medications, some ulcer drugs and certain other medications can impair sperm production and decrease male fertility.
- Prior surgeries. Certain surgeries may prevent you from having sperm in your ejaculate, including vasectomy, inguinal hernia repairs, scrotal or testicular surgeries, prostate surgeries, and large abdominal surgeries performed for testicular and rectal cancers, among others. In most cases, surgery can be performed to either reverse these blockage or to retrieve sperm directly from the epididymis and testicles.
Are there environmental causes of male infertility?
Overexposure to certain environmental elements such as heat, toxins and chemicals can reduce sperm production or sperm function. Specific causes include:
- Industrial chemicals. Extended exposure to benzenes, toluene, xylene, pesticides, herbicides, organic solvents, painting materials and lead may contribute to low sperm counts.
- Heavy metal exposure. Exposure to lead or other heavy metals also may cause infertility.
- Radiation or X-rays. Exposure to radiation can reduce sperm production, though it will often eventually return to normal. With high doses of radiation, sperm production can be permanently reduced.
- Overheating the testicles. Frequent use of saunas or hot tubs, or long periods of time in a bike sadle may temporarily lower your sperm count. Sitting for long periods, wearing tight clothing or working on a laptop computer for long stretches of time also may increase the temperature in your scrotum and slightly reduce sperm production. The type of underwear you wear is unlikely to make a significant difference in male fertility.
What other lifestyle factors can affect fertility?
- Illegal drug use. Anabolic steroids taken to stimulate muscle strength and growth can cause the testicles to shrink and sperm production to decrease. Use of cocaine or marijuana may temporarily reduce the number and quality of your sperm as well.
- Alcohol use. Drinking alcohol can lower testosterone levels, cause erectile dysfunction and decrease sperm production. Liver disease caused by excessive drinking also may lead to fertility problems.
- Occupation. Certain occupations can increase your risk of infertility, including those associated with extended use of computers or video display monitors, shift work, and work-related stress.
- Tobacco smoking. Men who smoke may have a lower sperm count than do those who don’t smoke. Secondhand smoke also may affect male fertility.
- Weight. Obesity can cause hormone changes that reduce male fertility.
For more information on male factor infertility, please visit the American Society for Reproductive Medicine’s patient information site Reproductivefacts.org or the Mayo Clinic website. You can also download this ASRM Practice Guideline.