Possible Reasons for Infertility

Maybe you and your partner are wondering if something is wrong. After all, you may have been trying to conceive for a while without any luck. It may be helpful to review some basic biology of fertility and conception. Or maybe you’re not having intercourse at the right time during the female partner’s reproductive cycle. Monitoring the basal body temperature (BBT) or cervical mucous changes will help to pinpointovulation times.

On the other hand, something physical may be wrong. What follows is an overview of conditions that may negatively affect the fertility of males and females. As you read, don’t jump to conclusions and self-diagnose. If you suspect something, you should talk to your healthcare provider orfertility specialist.


When it comes to fertility, the hormonal control of the menstrual cycle can be extremely complex. Below is a short list of conditions that can cause fertility problems. If you’re concerned that one of them may affect you, speak to your healthcare provider. The good news is that treatments may be available for many of these conditions.

Ovulatory problems
Approximately 33% to 50% of all infertile women have problems with ovulation. The normal ovarian cycle is so complex that even small changes may disrupt the cycle and prevent ovulation.

In the majority of cases, the problem is caused by hormonal imbalances (e.g., not having enough of a certain hormone or not releasing a hormone at the right time). Often this may be caused by improper communication between thehypothalamus in the brain and the pituitary gland. Sometimes, abnormal ovulation may also be associated with extremely low body weight or with being overweight, as well as any significant change in weight (loss or gain).

A woman’s fertility naturally declines as she gets older. If you’re 35 or older, and you’ve been unable to conceive after 6 months of unprotected, regular intercourse, you should talk to a health care provider.

Maternal age and fertility

Anatomical problems

Blocked fallopian tubes
Sometimes a woman’s fallopian tubes get blocked due to past infections, such as pelvic inflammatory disease (PID), or by abdominal surgery. Sexually transmitted diseases (STDs) can also cause scarring and damage to the fallopian tubes, causing blockages. Blocked tubes can interfere with the sperm and egg uniting or, if they do unite, prevent the embryo from implanting itself in the uterus. Often women with blocked fallopian tubes don’t experience any symptoms. Treatment of tubal problems or pelvic scarring may require specialized surgery, depending upon a woman’s situation. To determine whether the fallopian tubes are blocked, doctors can usehysterosalpingography. In this procedure, X-rays are taken after a radiopaque dye is injected through the cervix. The dye outlines the interior of the uterus and fallopian tubes. This procedure is performed shortly after a woman’s menstrual period ends.

Cervical mucus problems
The mucus in the cervix (the passage between the vagina and the uterus) changes during the menstrual cycle. Usually it is too thick for sperm to pass through, but around the time of ovulation, it becomes more elastic, less acidic (higher pH), and easier for sperm to penetrate. These changes help the sperm reach the fallopian tubes, where they can fertilize the egg. If the mucus remains thick around the time of ovulation, it may be harder for sperm to reach the egg, reducing the chances of pregnancy. The cervical mucus may also be hostile to sperm: some women have substances calledantibodies (produced by the immune system) within their cervical mucus that kill sperm. Infections of the cervix can also make the mucus hostile to sperm. If your doctor thinks cervical mucus problems may be an issue, you may be asked to undergo a post-coital test. This test, which is done after intercourse around the time ofovulation, looks at the cervical mucus to see if it is too thick or if it is hostile to sperm. If so, your doctor may recommend intrauterine insemination (IUI), a procedure that inserts the sperm directly into the uterus so that they don’t have to cross the cervical mucus.

Endometriosis is a disease in which cells that normally line the uterine cavity also implant outside the uterus on the ovaries or other pelvic organs. This condition is found in about 35% of women who have no other diagnosable infertility problems. There is no direct correlation between the severity of the endometriosis symptoms and the extent of disease. In fact, some women with a large amount of endometriosis may feel no discomfort. Surgery and or medications may alleviate the problem.

Polycystic ovarian syndrome (PCOS)
Polycystic ovarian syndrome (PCOS) is one of the leading causes of infertility, affecting an estimated 5% to 10% of women of childbearing age. PCOS is a condition in which cysts develop in the ovaries due to abnormal hormone levels. The ovaries can then enlarge. Symptoms may include irregular or absent periods, high blood pressure, acne, elevated insulin levels, excess hair on the face and body, and weight problems. PCOS may be difficult to diagnose, and often only the symptoms are treated – the underlying cause can be missed or not treated. Treatment of PCOS will vary depending on the individual.

Cancer treatments
Depending upon the location of treatment and the drug and dosage used, chemotherapy and radiation can contribute to difficulty conceiving. If you are diagnosed with cancer and are interested in understanding options in fertility preservation, speak to your oncologist or contact your fertility specialist right away.

Lifestyle factors

A low or high body mass may affect a woman’s fertility. Individuals with a BMI of under 18.5 or over 30 may have an increased risk of miscarriage or disrupted menstrual cycle. To calculate your BMI, click here. Modification of your lifestyle may also be necessary.

Alcohol and smoking
Alcohol consumption has been shown to affect a woman’s fertility. Smoking has been shown to increase the risk of tubal pregnancies, cervical cancer, and pelvic infections. Alcohol use and smoking may both have an impact on sperm quality as well.

It is important to highlight these factors and the duration of attempted conception for your doctor. Consider completing a doctor discussion guide before your appointment.


There are many reasons why a man may have difficulty with fertility. Fortunately, once diagnosed, some of these causes may be treatable.

If you have any concerns about your health or about any of the following conditions, you should talk to your health care provider as soon as possible.

Sperm disorders
Many fertility problems can be related to sperm disorder. Of the millions of sperm normally deposited into the vagina, only a few hundred will get close to the egg and have a chance to fertilize it. Several factors play a role in determining whether or not the sperm will succeed:

  • sperm count (number of sperm)
  • sperm motility (ability to move)
  • forward progression (quality of movement)
  • sperm size and shape

A deficiency in any of these factors may cause fertility difficulties. Although sperm count is important, sperm motility and forward progression appear to be even more crucial in determining the likelihood of sperm fertilizing the egg. Despite a low sperm count, many men with high-quality sperm may still be fertile. A simple test semen analysis can be done at your doctor’s office to determine sperm quality.

A variety of conditions can play in a role in causing sperm disorders.

The effect of aging on male fertility is not clear; however, evidence is growing that it may be a factor. Generally, a man’s fertility starts declining at around age 35 as the quality of a man’s sperm may diminish. In addition, sperm motility can also decline with age. Fertilization rates are usually over 60% for men under 39, but for those over that age, the rates fall to slightly over half.

Immunological disorders
Problems with the immune system can cause a man’s body to treat sperm as if it were a foreign matter. As a result, the immune system may produce antibodies to fight and destroy the sperm. In the general population this occurs in only 1% to 2% of men, but within that small population there is a 40% reduction in fertility.

Cancer treatments
Depending upon the location of the treatment and the drug and dosage used, chemotherapy and radiation may contribute to fertility problems. Many of the platinum-based chemotherapy treatments can be particularly damaging, as can radiation to the genital and surrounding areas (such as testicular cancer). For more information on fertility preservation before cancer treatment, talk to your oncologist or a fertility specialist.

Sexually transmitted infections (STIs)
STIs may damage the parts of the body that transport sperm through the reproductive tract. Talk to your doctor about how STIs may affect your fertility, how to reduce your risk, and whether you should be tested.

Medical conditions, lifestyle, and environmental factors

High temperatures
Prolonged exposure to high heat from hot baths, steam rooms, or even tight underwear may lower sperm production.

Occupational risks
Exposure to toxic substances on the job, such as pesticides, radioactivity, X-rays, and electromagnetic or microwave emissions may lead to sperm abnormalities. If you’ve been exposed or if you’re concerned about occupational hazards, talk to your health care provider.

Diseases, drug use, and medications
Occasionally, the presence of diseases such as diabetes, central nervous system problems, and pituitary tumours may affect a man’s fertility. In addition, some drugs for heart disease and high blood pressure may also be risk factors.

Smoking, alcohol, and drug use may also have a negative effect on man’s fertility.

A number of lubricants used during intercourse, such as petroleum jelly or vaginal creams, have been shown to have a negative effect on sperm quality.

Scrotal varicocele
Varicocele is one of the most commonly identifiable causes of male infertility. Varicocele is a varicose vein around a testicle that may hinder sperm production. It is found in about 15% of normal males and in approximately 40% of infertile men, most often on the left side or simultaneously on both sides.

Retrograde ejaculation
Retrograde ejaculation involves the ejaculate flowing backward into the bladder instead of leaving the penis. There is a sphincter (a ring-shaped muscle) that controls the flow of fluid between the urethra (which carries urine and semen) and the bladder. Normally the sphincter of the bladder contracts and the sperm go to the urethra towards the area of least pressure. In retrograde ejaculation, this sphincter does not function properly. Causes may be in the autonomic nervous system or the operation of the prostate. Retrograde ejaculation is a common complication of trans-urethral resection of the prostate, a procedure used to treat prostate cancer or an enlarged prostate. In this procedure, prostate tissue is removed, slice by slice, through a resectoscope passed along the urethra.

Retrograde ejaculation may be a side effect of medications used to relax the muscles of the urinary tract for various purposes. These medications may cause the bladder sphincter to relax as well and to fail to contract fully. Other types of medications that may be associated with this side effect include antidepressants and antipsychotics.

Retrograde ejaculation can also be a complication of diabetes, especially for persons with long-term poor blood sugar control. This is due to damage of the nerve supplying the bladder sphincter.

Retrograde ejaculation may cause a couple to experience infertility, as most sperm do not get to the vagina and the rest of the female reproductive system.

Undescended testis
An undescended testis is one that has failed to complete its normal passage from within the abdomen to reach its normal position in the scrotum. This condition is present in about 3% of newborns, with fewer than 1% needing treatment. Testicles that don’t descend into the scrotum are not likely to function normally. Because they may not make sperm, they can cause fertility difficulties.

Erectile dysfunction (ED)
Erectile dysfunction (ED), sometimes called “impotence,” is the repeated inability to get or keep an erection firm enough for sexual intercourse. The word “impotence” may also be used to describe other problems that interfere with sexual intercourse and reproduction, such as lack of sexual desire and problems with ejaculation or orgasm. An erection is essential for ejaculation.

ED may be treatable at any age, and awareness of this fact has been growing. Many men have sought help and returned to normal sexual activity after speaking to their doctor and finding an appropriate treatment.

Reference: Fertility LifeLinesTM