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Diseases & Conditions
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If you've tried to conceive for more
than a year, you or your partner may be infertile. Pregnancy may be a
challenge, not an impossibility.
Infertility, also known as subfertility, is the
inability to conceive a child within one year.
Infertility may be due to a single cause in either
you or your partner, or a combination of factors
that may prevent a pregnancy from occurring or
continuing.
Infertility differs from sterility. Being sterile
means you're unable to conceive a child. With
sterility, you or your partner has a physical
problem that precludes the ability to conceive. A
diagnosis of infertility simply means that becoming
pregnant may be a challenge rather than an
impossibility.
The human reproductive process is complex. To
accomplish a pregnancy, the intricate processes of
ovulation and fertilization need to work just right.
For many couples attempting pregnancy, something
goes wrong in one or both of these complex processes
and causes infertility.
Infertility affects more than 6 million American
couples, with the male partner being either the sole
or a contributing cause in approximately 40 percent
of infertile couples. Problems with female fertility
are present about one-half to two-thirds of the
time. In both men and women, multiple factors can
account for difficulty with fertility.
Signs and symptoms
Most men with fertility problems have no signs or symptoms. Some men
with hormonal problems may note a change in their voice or pattern of
hair growth, enlargement of their breasts, or difficulty with sexual
function. Infertility in women may be signaled by irregular menstrual
periods or associated with conditions that cause pain during
menstruation or intercourse.
Causes
Because of the intricate series of events required to begin a pregnancy,
many factors may cause a delay in starting your family.
Every month the pituitary gland in a woman's brain sends a signal to her
ovaries to prepare an egg for ovulation. The pituitary hormones
follicle-stimulating hormone (FSH) and luteinizing hormone (LH) are
involved in stimulating the ovaries to bring an egg to ovulation. A
large boost in LH carries a message to the ovarian follicle to release
its egg (ovulate). A woman is most fertile at the time of ovulation
around day 14 of her menstrual cycle although the exact time of
ovulation varies among women due to different lengths of menstrual
cycles.
Every month, hormones signal a woman's ovaries to prepare an egg for
ovulation....During each menstrual cycle, an egg is released by one of
the ovaries (ovulation). The egg travels into the fallopian tube. If
fertilization is to occur, sperm ejaculated into the vagina must swim up
...For fertilization to occur, sperm produced in the testicles and
ejaculated into the vagina must swim up the uterus and into the
fallopian tube where one sperm penetrates the egg....
The egg is then captured by a fallopian tube and is viable for about 24
hours, but its best chance of being fertilized is within the first 12
hours following ovulation. For pregnancy to occur, a sperm must unite
with the egg in the fallopian tube within this time. Sperm are capable
of fertilizing the egg for up to 72 hours and must be present in the
fallopian tube at the same time as the egg for conception to occur. If
fertilized, the egg moves into the uterus two to four days later. There
it attaches to the uterine lining and begins a nine-month process of
growth.
In order for sperm to reach the egg, many factors are involved in the
male fertility process. There must be enough sperm, they must be of the
right shape, and they must move in the right way. There must be enough
semen to transport the sperm. The man also needs to be able to have an
erection, and must be able to ejaculate the semen and deliver it into
the vagina.
The cause of infertility can involve one or both partners. Sometimes the
problem isn't really one of infertility, but a more general sexual
problem such as erectile dysfunction. Other times, the problem may
involve an abnormality in the structure of the reproductive hormones or
organs. Certain infections and diseases also can affect fertility.
Male infertility
A
number of causes exist for male infertility that may result in impaired
sperm count or mobility, or impaired ability to fertilize the egg. The
most common causes of male infertility include abnormal sperm production
or function, impaired delivery of sperm, conditions related to a man's
general health and lifestyle, and overexposure to certain environmental
elements:
Abnormal sperm production or function.
More than 90 percent of male infertility cases are due to sperm
abnormalities, such as:
-
Impaired shape
and movement of sperm.
Sperm must be properly shaped and able to move rapidly and
accurately toward the egg for fertilization to occur. If the shape
and structure (morphology) of the sperm is abnormal or the movement
(motility) is impaired, sperm may not be able to reach the egg.
-
Absent sperm
production in testicles.
Complete failure of the testicles to produce sperm is rare,
affecting less than 5 percent of infertile men.
-
Low sperm
concentration.
A sperm count of 13.5 million per milliliter of semen or fewer
indicates low sperm concentration (subfertility). A count of 48
million per milliliter of semen or higher indicates fertility.
-
Varicocele.
A varicocele is a varicose vein in the scrotum that may prevent
normal cooling of the testicle and raise testicular temperature,
preventing sperm from surviving.
-
Undescended
testicle (cryptorchidism).
This occurs when one or both testicles fail to descend from the
abdomen into the scrotum during fetal development. Undescended
testicles can cause mild to severely impaired sperm production.
Because the testicles are exposed to the higher degree of internal
body heat, sperm production may be affected.
-
Testosterone
deficiency (male hypogonadism).
Infertility can result from disorders of the testicles themselves,
or an abnormality affecting the hypothalamus or pituitary glands in
the brain that produce the hormones that control the testicles.
-
Klinefelter's
syndrome.
In this disorder of the sex chromosomes, a man has two X chromosomes
and one Y chromosome instead of one X and one Y. This causes
abnormal development of the testicles, resulting in low or absent
sperm production. Testosterone production also may be lower.
-
Infections.
Infection may temporarily affect sperm motility. Repeated bouts 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. Mycoplasma is
an organism that may fasten itself to sperm cells, making them less
motile. If mumps, a viral infection usually affecting young
children, occurs after puberty, inflammation of the testicles can
impair sperm production. Inflammation of the prostate (prostatitis),
urethra or epididymis also may alter sperm motility.
In many instances, no cause for reduced sperm production is found. When
sperm concentration is less than 5 million per milliliter of semen,
genetic causes could be involved. A blood test can reveal whether there
are subtle changes in the Y chromosome.
Impaired delivery of sperm.
Problems with the delivery of sperm from the penis into the vagina can
cause infertility. These may include:
-
Sexual issues.
Often treatable, problems with sexual intercourse or technique may
affect fertility. Difficulties with erection of the penis (erectile
dysfunction), premature ejaculation, painful intercourse (dyspareunia),
or psychologic or relationship problems can contribute to
infertility. Use of lubricants such as oils or petroleum jelly can
be toxic to sperm and impair fertility.
-
Retrograde
ejaculation.
This occurs when semen enters the bladder during orgasm rather than
emerging out through the penis. Various conditions can cause
retrograde ejaculation including diabetes, bladder, prostate or
urethral surgery, and the use of psychiatric or antihypertensive
drugs.
-
Blockage of
epididymis or ejaculatory ducts.
Some men are born with blockage of the part of the testicle that
contains sperm (epididymis) or ejaculatory ducts. An estimated 2
percent of men who seek treatment for infertility lack the tubes
that carry sperm (vas deferens).
-
No semen
(ejaculate).
The absence of ejaculate may occur in men with spinal cord injuries
or diseases. This fluid transports sperm through the penis into the
vagina.
-
Misplaced
urinary opening (hypospadias).
A birth defect can cause the urinary (urethral) opening to be
abnormally located on the underside of the penis. If not surgically
corrected, this condition can prevent sperm from reaching the
cervix.
-
Antisperm
antibodies.
Antibodies that target sperm and weaken or disable them usually
occur after surgical blockage of part of the vas deferens for male
sterilization (vasectomy). Presence of these antibodies may
complicate the reversal of a vasectomy.
-
Cystic
fibrosis.
Men with cystic fibrosis often have missing or obstructed vas
deferens.
General health and lifestyle.
A man's general health and lifestyle may affect fertility. Some common
causes of infertility related to health and lifestyle include:
-
Emotional
stress.
Stress may interfere with certain hormones needed to produce sperm.
Your sperm count may be affected if you experience excessive or
prolonged emotional stress. A problem with fertility itself can
sometimes become long term and discouraging, producing more stress.
Infertility can affect social relationships and sexual functioning.
-
Malnutrition.
Deficiencies in nutrients such as vitamin C, selenium, zinc and
folate may contribute to infertility.
-
Obesity.
Increased body mass may be associated with fertility problems in
men.
-
Cancer and its
treatment.
Both radiation and chemotherapy treatment for cancer can impair
sperm production, sometimes severely. The closer radiation treatment
is to the testicles, the higher the risk of infertility. Removal of
one or both testicles due to cancer also may affect male fertility.
You may want to consider freezing (cryopreserving) your sperm before
cancer treatment to ensure future fertility.
-
Alcohol and
drugs.
Alcohol or drug dependency can be associated with general ill health
and reduced fertility. The use of certain drugs also can contribute
to infertility. Anabolic steroids, for example, which are taken to
stimulate muscle strength and growth, can cause the testicles to
shrink and sperm production to decrease.
-
Other medical
conditions.
A severe injury or major surgery can affect male fertility. Certain
diseases or conditions, such as diabetes, thyroid disease, HIV/AIDS,
Cushing's syndrome, anemia, heart attack, and liver or kidney
failure, may be associated with infertility.
-
Age.
A gradual decline in fertility is common in men older than 35.
Environmental exposure.
Overexposure to certain environmental elements such as heat, toxins and
chemicals can reduce sperm count either directly by affecting testicular
function or indirectly by altering the male hormonal system. Specific
causes include:
-
Pesticides and
other chemicals.
Herbicides and insecticides may cause female hormone-like effects in
the male body and may be associated with reduced sperm production.
Exposure to such chemicals also may contribute to testicular cancer.
Men exposed to hydrocarbons, such as ethylbenzene, benzene, toluene,
xylen and aromatic solvents used in paint, varnishes, glues, metal
degreasers and other products, may be at risk of infertility. Men
with high exposure to lead also may be more at risk.
-
Testicular
exposure to overheating.
Frequent use of saunas or hot tubs can elevate your core body
temperature. This may impair your sperm production and lower your
sperm count.
-
Substance
abuse.
Cocaine or heavy marijuana use may temporarily reduce the number and
quality of your sperm.
-
Tobacco
smoking.
Men who smoke may have a lower sperm count than do those who don't
smoke.
Female infertility
The
most common causes of female infertility include fallopian tube damage
or blockage, endometriosis, ovulation disorders, elevated prolactin,
polycystic ovary syndrome, early menopause, benign uterine fibroids, and
pelvic adhesions:
Fallopian tube damage or blockage.
This condition usually
results from inflammation of the fallopian tube (salpingitis). Chlamydia
is the most frequent cause. Tubal inflammation may go unnoticed or cause
pain and fever.
Tubal damage with scarring is the major risk factor of a pregnancy in
which the fertilized egg is unable to make its way through the fallopian
tube to implant in the uterus (ectopic pregnancy). One episode of tubal
infection may cause fertility difficulties. The risk of ectopic
pregnancy increases with each occurrence of tubal infection.
Endometriosis.
Endometriosis occurs
when the tissue that makes up the lining of the uterus grows outside of
the uterus. This tissue most commonly is implanted on the ovaries or the
lining of the abdomen near the uterus, fallopian tubes and ovaries.
These implants respond to the hormonal cycle and grow, shed and bleed in
sync with the lining of the uterus each month, which can lead to
scarring and inflammation. Pelvic pain and infertility are common in
women with endometriosis.
Infertility in endometriosis also may be due to:
-
Ovarian cysts (endometriomas).
Ovarian cysts may indicate advanced endometriosis and often are
associated with reduced fertility. Endometriomas can be treated with
surgery.
-
Scar tissue.
Endometriosis may cause rigid webs of scar tissue between the
uterus, ovaries and fallopian tubes. This may prevent the transfer
of the egg to the fallopian tube.
Ovulation disorders.
About 25 percent of
female infertility is caused by ovulation disorders. Disruption in the
part of the brain that regulates ovulation (hypothalamic-pituitary axis)
can cause deficiencies in luteinizing hormone (LH) and
follicle-stimulating hormone (FSH). Even slight irregularities in the
hormone system can affect ovulation.
Specific causes of hypothalamic-pituitary disorders include:
Elevated prolactin (hyperprolactinemia).
The hormone prolactin stimulates breast milk production. High levels in
women who aren't pregnant or nursing may affect ovulation. An elevation
in prolactin levels may also indicate the presence of a pituitary tumor.
Some drugs can elevate levels of prolactin. Milk flow not related to
pregnancy or nursing (galactorrhea) can be a sign of high prolactin.
Polycystic ovary syndrome (PCOS). An increase in androgen hormone
production causes PCOS. In women with increased body mass, elevated
androgen production may come from stimulation by higher levels of
insulin. In lean women, the elevated levels of androgen may be
stimulated by a higher ratio of luteinizing hormone (LH). Lack of
menstruation (amenorrhea) or infrequent menses (oligomenorrhea) are
common symptoms in women with PCOS.
In PCOS, increased androgen production prevents the follicles of the
ovaries from producing a mature egg. Small follicles that start to grow
but can't mature to ovulation remain within the ovary. A persistent lack
of ovulation may lead to mild enlargement of the ovaries.
Without ovulation, the hormone progesterone isn't produced and estrogen
levels remain constant. Elevated levels of androgen may cause increased
dark or thick hair on the chin, upper lip or lower abdomen as well as
acne and oily skin.
Early menopause (premature ovarian failure).
Early menopause is the absence of menstruation and the early depletion
of ovarian follicles before age 35. Although the cause is often unknown,
certain conditions are associated with early menopause, including:
-
Autoimmune
disease. The body produces antibodies to attack its own tissue, in
this case the ovary. This may be associated with hypothyroidism (too
little thyroid hormone).
-
Radiation or
chemotherapy for the treatment of cancer
-
Tobacco smoking
Benign uterine fibroids.
Fibroids are benign
tumors in the wall of the uterus and are common in women in their 30s.
Occasionally they may cause infertility by interfering with the contour
of the uterine cavity, blocking the fallopian tubes.
Pelvic adhesions.
Pelvic adhesions are bands of scar tissue that bind organs after pelvic
infection, appendicitis, or abdominal or pelvic surgery. They may limit
the functioning of the ovaries and fallopian tubes and impair fertility.
Scar tissue formation inside the uterine cavity after a surgical
procedure may result in a closed uterus and ceased menstruation (Asherman's
syndrome). This is most common following surgery to control uterine
bleeding after giving birth.
Other causes.
A number of other causes can lead to infertility in women:
-
Medications.
Temporary infertility may occur with the use of
certain medications. In most cases, fertility is restored when the
medication is stopped.
-
Thyroid
problems.
Disorders of the
thyroid gland, either too much thyroid hormone (hyperthyroidism) or
too little (hypothyroidism), can interrupt the menstrual cycle and
cause infertility.
-
Cancer and its
treatment.
Certain cancers
particularly female reproductive cancers often severely impair
female fertility. Both radiation and chemotherapy may affect a
woman's ability to reproduce. Chemotherapy may impair reproductive
function and fertility more severely in men than in women.
-
Other
medical conditions.
Medical conditions
associated with delayed puberty or amenorrhea, such as Cushing's
disease, sickle cell disease, HIV/AIDS, kidney disease and diabetes,
can affect female fertility.
Risk factors
Many of the risk factors for both male and female infertility are the
same. These include:
-
Age.
Age is the strongest predictor of female fertility. After about age
32, a woman's fertility potential declines. A woman does not renew
her oocytes (eggs). There is no one special point when fertility
declines it's a gradual transition.
-
Chromosomal
abnormalities.
Infertility in older women may be due to a higher risk of
chromosomal abnormalities that occur in the eggs as they age. Older
women are also more likely to have health problems that may
interfere with fertility. The risk of miscarriage also increases
with a woman's age. A gradual decline in fertility is possible in
men older than 35.
-
Tobacco
smoking.
Women who smoke tobacco may reduce their chances of becoming
pregnant and the possible benefit of fertility treatment.
Miscarriages are more frequent in women who smoke.
-
Alcohol.
There's no certain level of safe alcohol use during conception or
pregnancy.
-
Body mass.
Extremes in body mass either too high (body mass index, or BMI, of
greater than 25.0) or too low (BMI of lower than 20.0) may affect
ovulation and increase the risk of infertility.
-
Being
overweight.
Among American women, infertility often is due to a sedentary
lifestyle and being overweight.
-
Being
underweight.
Women at risk include those with eating disorders, such as anorexia
nervosa or bulimia, and women on a very low-calorie or restrictive
diet. Strict vegetarians also may experience infertility problems
due to a lack of important nutrients such as vitamin B-12, zinc,
iron and folic acid. Marathon runners, dancers and others who
exercise very intensely are more prone to menstrual irregularities
and infertility.
When to seek medical advice
In general, don't be concerned about infertility unless you and your
partner have been trying to conceive regularly for at least one year.
However, if you're a woman older than 30 or haven't had a menstrual flow
for longer than six months, seek a medical evaluation. If you have a
history of irregular or painful menstrual cycles, pelvic pain,
endometriosis, pelvic inflammatory disease (PID) or repeated
miscarriages, schedule a consultation with your doctor sooner. If you're
a man with a low sperm count or a history of testicular, prostate or
sexual problems, consider seeking help earlier.
Screening and diagnosis
If you and your partner are unable to achieve conception within a
reasonable time and would like to do so, seek help. The woman's
gynecologist, the man's urologist or your family physician can determine
whether there's a problem that requires a specialist or clinic that
treats infertility problems.
One-fourth of infertile couples have more than one cause of their
infertility. Thus, your physician will usually begin a comprehensive
infertility examination of both you and your partner.
Before undergoing infertility testing, be aware that a certain amount of
commitment is required. Your physician or clinic will need to determine
what your sexual habits are and may make recommendations about how you
may need to change those habits. The tests and periods of trial and
error may extend over several months.
Evaluation is expensive and in some cases involves operations and
uncomfortable procedures, and the expenses may not be reimbursed by many
medical plans. Finally, there's no guarantee, even after all testing and
counseling, that conception will occur. However, for couples who are
eager to have their own child, such an evaluation is best. It may result
in a successful pregnancy.
Tests for men
For
a man to be fertile, the testicles must produce enough healthy sperm,
and the sperm must be ejaculated effectively into the woman's vagina.
Tests for male infertility attempt to determine whether any of these
processes are impaired.
The first step is a general physical examination. This includes
examination of your genitals and questions concerning your medical
history, illnesses and disabilities, medications, and sexual habits.
Your doctor may ask for a specimen of ejaculated semen. This is
generally obtained by masturbating or by interrupting intercourse and
ejaculating your semen into a clean container. Your doctor will provide
instructions. Such a specimen may be required more than once.
A
laboratory analyzes your semen specimen for quantity, color and presence
of infections or blood. Detailed analysis of the sperm also is done. The
laboratory will determine the number of sperm present and any
abnormalities in the shape and movement (motility) of the sperm. Often
sperm counts fluctuate from one specimen to the next.
Other tests are sometimes required of the man. A blood test to determine
the level of testosterone and other hormones is common.
Tests for women
For
a woman to be fertile, the ovaries must release healthy eggs regularly,
and her reproductive tract must allow the eggs and sperm to pass into
her fallopian tubes for a possible union. Her reproductive organs must
be healthy and functional.
After your doctor asks questions regarding your health history,
menstrual cycle and sexual habits, a general physical examination is
done. This includes a regular gynecologic examination. Specific
fertility tests may include:
-
Confirmation of
ovulation.
A blood test is sometimes performed to determine the levels of
hormones involved in successful ovulation.
-
Hysterosalpingography.
This test evaluates the condition of your uterus and fallopian
tubes. Fluid is injected into your uterus, and an X-ray is taken to
determine whether the fluid progresses out of the uterus and into
your fallopian tubes and general peritoneal cavity. Blockage or
problems often can be located and may be corrected with medication
or surgery.
-
Laparoscopy.
Performed under general anesthesia, this procedure involves
inserting a thin viewing device into your abdomen and pelvis to
examine your fallopian tubes, ovaries and uterus. A small incision
(8 to 10 millimeters) is made beneath your navel, and a needle is
inserted into your abdominal cavity. A small amount of gas (usually
carbon dioxide) is inserted into the abdomen to create space for
entry of the laparoscope an illuminated, fiber-optic telescope.
-
The most common
problems identified by laparoscopy are endometriosis and scarring.
Your doctor can also detect blockages or irregularities of the
fallopian tubes and uterus. Often a blue dye is injected into the
cervical canal and through the uterus and fallopian tubes to
determine whether they are open. At the end of the procedure, the
gas and laparoscope are drawn out and the incision is closed.
Laparoscopy generally is done on an outpatient basis.
-
Basal body
temperature.
Although this test was once a standard, basal body temperature
charting is used less often today. Charting a woman's body
temperature doesn't give as precise time of ovulation as earlier
believed.
-
Urinary
luteinizing hormone (LH) detector kits.
A number of at-home kits are available to test your LH level.
Although these kits may be helpful, they also can be inaccurate and
misleading. Consult your doctor before using one.
Not everyone needs to undergo all, or even many, of these tests before
the cause of infertility is found. Which tests are used and their
sequence depend on discussion and agreement between you and your doctor.
Unexplained infertility
In
about one-fifth of infertile couples, no specific cause is found
(unexplained infertility). Couples receiving the diagnosis of
unexplained infertility are more likely to seek multiple health care
providers and be influenced by the experiences of family and friends or
literature that promises new hope. Although infertility is unexplained,
the pregnancy rate for these couples is among the highest.
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