Infertility is often defined as not being able to get pregnant in spite of having frequent, unprotected sex for at least a year. If you and your partner are experiencing difficulty becoming pregnant, you are not on your own. An estimated 10-15 percent of couples in the United States are infertile.
If you’ve been trying to conceive for more than a year, there’s a chance that something may be interfering with your efforts to have a child. Infertility may be attributed to one issue in either you or your partner, or a variety of factors may prevent a pregnancy from occurring or continuing.
A number of factors can weaken sperm count or mobility, or worsen the ability to fertilize the egg. The most common causes of male infertility include irregular sperm production or function, impaired delivery of sperm, general health and lifestyle issues, and excessive exposure to certain environmental elements.
Reduced production or function of sperm
Many cases of male infertility are due to problems with the sperm, such as:
- Irregular shape and movement of sperm. Normal sperm shape and the ability for sperm to move rapidly and accurately toward the egg is crucial for fertilization to occur. If the sperm morphology (shape and structure) are abnormal or the movement is impaired, sperm may not be able to access or penetrate the egg.
- Below normal sperm concentration. Normal sperm concentration is defined as greater than or equal to 20 million sperm per milliliter of semen. Sperm counts of 10 million or fewer per milliliter of semen indicate low sperm concentration. Absolute failure of the testicles to produce sperm is uncommon, affecting very few infertile men.
- Varicocele. This is known as a varicose vein in the scrotum that could prevent normal cooling of the testicle, which may cause reduced sperm count and movement.
- Undescended testicle. This condition occurs when one or both testicles fail to move from the abdomen into the scrotum during fetal development. Due to the fact that the testicles are exposed to the higher internal body temperature, when compared with the temperature in the scrotum, sperm production may be affected.
- Testosterone deficiency. Infertility may result from disorders of the testicles themselves, or an irregularity affecting the hypothalamus or pituitary gland in the brain that produces the hormones that control the testicles.
- Genetic defects. Klinefelter’s syndrome is a genetic defect that occurs when a man has two X chromosomes and one Y chromosome instead of one X and one Y. This causes unusual development of the testicles, resulting in low or absent sperm production and possible low testosterone.
- Infections. Sperm motility can be temporarily affected by certain infections. Repeated attacks of sexually transmitted diseases (STDs), such as chlamydia and gonorrhea, are most often associated with male infertility. These infections can cause scarring and block sperm passage. An occurrence of mumps after puberty may cause inflammation of the testicles and can impair sperm production. Inflammation of the prostate, urethra or epididymis also may alter sperm motility.
In many cases, no cause for reduced sperm production is found. If sperm concentration is less than five million per milliliter of semen, genetic causes may be involved. Slight changes in the Y chromosome can be revealed by a blood test.
Delivery of sperm impaired
Complications with the delivery of sperm from the penis into the vagina can result in infertility. These may include:
- Sexual issues. Often treatable, problems with sexual intercourse or technique may affect fertility. Erectile dysfunction, premature ejaculation, painful intercourse or psychological or relationship problems can contribute to infertility.
- Retrograde ejaculation. Semen enters the bladder during orgasm instead of emerging out through the penis. Diabetes, bladder, prostate or urethral surgery, and the use of certain medications may cause retrograde ejaculation.
- Epididymis or ejaculatory ducts blockage. In some cases, men are born with blockage of the part of the testicle that contains sperm, the epididymis or ejaculatory ducts. Certain men lack the tube that carries sperm (vas deferens) from the testicle out to the opening in the penis.
- No semen (ejaculate). Men with spinal cord injuries or diseases may experience the absence of ejaculate. The sperm is carried from the penis into the vagina by the ejaculate.
- Misplaced urinary opening. A defect at birth may cause the urinary opening to be unusually located on the underside of the penis. The condition may prevent sperm from reaching the woman’s cervix if not surgically corrected.
General health and lifestyle
Frequent causes of infertility related to health and lifestyle include:
- Emotional stress. Stress may hinder certain hormones needed to produce sperm. Extreme or prolonged emotional stress may affect your sperm. Fertility problems can sometimes become long term and disappointing, producing more stress. Social relationships and sexual performance can affect infertility.
- Malnutrition. Certain vitamin deficiencies such as C, selenium, zinc and folate may contribute to infertility.
- Obesity. Unhealthy body weight may contribute to fertility problems in men.
- Alcohol and drugs. Excessive alcohol use or drug dependency may be associated with poor health and lowered fertility.
- Other medical conditions. Male fertility can be affected by severe injury or major surgery. Diabetes, thyroid disease or anemia may be linked to infertility.
- Age. Men older than 35 may experience a gradual decline in fertility.
Excessive exposure to environmental elements such as heat, toxins and chemicals may lead to a reduced sperm count, either direct or indirect. Examples include:
- Pesticides and other chemicals. Studies have shown that herbicides and insecticides can cause female hormone-like effects in the male body and furthermore may be associated with reduced sperm production and testicular cancer. Exposure to lead may also cause infertility.
- Overheating the testicles. Regular use of saunas or hot tubs can increase your core body temperature. This may interfere your sperm production and lower your sperm count.
- Substance abuse and tobacco smoking. Substance abuse and smoking tobacco products may temporarily reduce the number and quality of a male’s sperm.