of Failure to Ovulate
are one of the most common reasons why women are unable to conceive, and
account for 30% of women's infertility. Fortunately, approximately
70% of these cases can be successfully treated by the use of drugs such
as Clomiphene and Menogan/Repronex. The causes of failed ovulation can
be categorized as follows:
These are the most common causes of anovulation. The process of ovulation
depends upon a complex balance of
hormones and their interactions to be successful, and any disruption in
this process can hinder ovulation. There are three
main sources causing this problem:
to produce mature eggs
50% of the cases of anovulation, the ovaries do not produce normal follicles
inwhich the eggs can mature. Ovulation is rare if the eggs are immature
and the chance of fertilization becomes almost nonexistent. Polycystic
ovary syndrome, the most common disorder responsible for this problem,
includes symptoms such as amenorrhoea, hirsutism, anovulation and infertility.
This syndrome is characterized by a reduced production of FSH, and normal
or increased levels of LH, oestrogen and testosterone. The current
hypothesis is that the suppression of FSH associated with this condition
causes only partial development of ovarian follicles, and follicular cysts
can be detected in an ultrasound scan. The affected ovary often becomes
surrounded with a smooth white capsule and is double its normal size.
The increased level of oestrogen raises the risk of breast cancer.
of the hypothalamus
is the portion of the brain responsible for sending signals to the pituitary
gland, which, in turn, sends hormonal stimuli to the ovaries in the form
of FSH and LH to initiate egg maturation. If the hypothalamus fails
to trigger and control this process, immature eggs will result. This
is the cause of ovarian failure in 20% of cases.
of the pituitary gland
responsibility lies in producing and secreting FSH and LH. The ovaries
will be unable to ovulate properly if either too much or too little of
these substances is produced. This can occur due to physical injury,
a tumor or if there is a chemical imbalance in the pituitary.
Physical damage to the ovaries may result in failed ovulation. For example,
extensive, invasive, or multiple surgeries, for
repeated ovarian cysts may cause the capsule of the ovary to become damaged
or scarred, such that follicles cannot mature
properly and ovulation does not occur. Infection may also have this
This presents a rare and as of yet unexplainable cause of anovulation.
Some women cease menstruation and begin
menopause before normal age. It is hypothesized that their natural
supply of eggs has been depleted or that the majority
of cases occur in extremely athletic women with a long history of
low body weight and extensive exercise. There is also
a genetic possibility for this condition.
Although currently unexplained, "unruptured follicle syndrome" occurs in
women who produce a normal follicle, with an egg
inside of it, every month yet the follicle fails to rupture. The
egg, therefore, remains inside the ovary and proper ovulation
does not occur.
of Poorly Functioning Fallopian Tubes
affects approximately 25% of infertile couples and varies widely, ranging
from mild adhesions to complete tubal blockage. Treatment for tubal
disease is most commonly surgery and, owing to the advances in microsurgery
and lasers, success rates (defined as the number of women who become pregnant
within one year of surgery) are as high as 30% overall,
procedures having success rates up to 65%. The main causes of tubal
Caused by both bacteria and viruses and usually transmitted sexually, these
infections commonly cause inflammation
resulting in scarring and damage. A specific example is Hydrosalpnix,
a condition in which the fallopian tube is occluded at
both ends and fluid collects in the tube.
The most common of these are appendicitis and colitis, causing inflammation
of the abdominal cavity which can affect the
fallopian tubes and lead to scarring and blockage.
This is an important cause of tubal disease and damage. Pelvic or
abdominal surgery can result in adhesions that alter the
tubes in such a way that eggs cannot travel through them.
This is a pregnancy that occurs in the tube itself and, even if carefully
and successfully overcome, may cause tubal damage
and is a potentially life-threatening condition.
In rare cases, women may be born with tubal abnormalities, usually associated
with uterus irregularities.
10% of infertile couples are affected by endometriosis. Endometriosis
affects five million US women, 6-7% of all females. In fact, 30-40%
of patients with endometriosis are infertile. This is two to three
times the rate of infertility in the general population. For women
with endometriosis, the monthly fecundity (chance of getting pregnant)
diminishes by 12 to 36%. This condition is characterized by excessive
growth of the lining of the uterus, called the endometrium. Growth
occurs not only in the uterus but also elsewhere in the abdomen, such as
in the fallopian tubes, ovaries and the pelvic peritoneum. A positive
diagnosis can only be made by diagnostic laparoscopy, a test that allows
the physician to view the uterus, fallopian tubes, and pelvic cavity directly.
The symptoms often associated with endometriosis include heavy, painful
and long menstrual periods, urinary urgency, rectal bleeding and premenstrual
spotting. Sometimes, however, there are no symptoms at all, owing
to the fact that there is no correlation between the extent of the disease
and the severity of the symptoms. The long term cumulative pregnancy
rates are normal in patients with minimal endometriosis and normal anatomy.
Current studies demonstrate that pregnancy rates are not improved by treating
variables that may cause infertility in women:
10% of all cases of female infertility are caused by an abnormal uterus.
Conditions such as fibroid, polyps,
adenomyosis may lead to obstruction of the uterus and Fallopian tubes.
abnormalities, such as septate uterus, may lead to recurrent miscarriages
or the inability to conceive.
3% of couples face infertility due to problems with the femaleís
cervical mucus. The mucus needs to
of a certain consistency and available in adequate amounts for sperm to
swim easily within it. The most common
for abnormal cervical mucus is a hormone imbalance, namely too little estrogen
or too much progesterone.
It is well-known that certain personal habits and lifestyle factors impact
health; many of these same factors may limit a
couple's ability to conceive. Fortunately, however, many of these
variables can be regulated to increase not only the
chances of conceiving but also one's overall health.
and Occupational Factors:
functioning requires both proper diet and appropriate levels of exercise.
Women who are significantly overweight or underweight may have difficulty
smoking has been shown to lower sperm counts in men and increases the risk
of miscarriage, premature birth, and low-birth-weight babies for women.
Smoking by either partner reduces the chance of conceiving with each cycle,
either naturally or by IVF, by one-third.
greatly increases the risk of birth defects for women and, if in high enough
levels in the motherís blood, may cause Fetal Alcohol Syndrome.
Alcohol also affects sperm counts in men.
as marijuana and anabolic steroids, may impact sperm counts in men.
Cocaine use in pregnant women may cause severe retardations and kidney
problems in the baby and is perhaps the worst possible drug to abuse while
pregnant. Recreational drug use should be avoided, both when trying to
conceive and when pregnant.
The ability to conceive may be affected by exposure to various toxins or
chemicals in the workplace or the surrounding
environment. Substances that can cause mutations, birth defects,
abortions, infertility or sterility are called reproductive
toxins. Disorders of infertility, reproduction, spontaneous abortion,
and teratogenesis are among the top ten work-related
diseases and injuries in the U.S. today. Despite the fact that considerable
controversy exists regarding the impacts of
toxins on fertility, four chemicals are now being regulated based on their
documented infringements on conception.
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lead sources has been proven to negatively impact fertility in humans.
Lead can produce teratospermias (abnormal sperm) and is thought to be an
abortifacient, or substance that causes artificial abortion.
Treatments and Materials
to radiation, ranging from simple x-rays to chemotherapy, has been shown
to alter sperm production, as well as contribute to a wide array of ovarian
used both in the sterilization of surgical instruments and in the manufacturing
of certain pesticides, ethylene oxide may cause birth defects in early
pregnancy and has the potential to provoke early miscarriage.
chemicals found in pesticides, such as DBCP, can cause ovarian problems,
leading to a variety of health conditions, like early menopause, that may
directly impact fertility.