Ovulatory disorders 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:
(1) Hormonal Problems
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:
- Failure to produce mature eggs
- Malfunction of the hypothalamus
- Malfunction of the pituitary gland
In approximately 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.
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.
The pituitary's 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 impact. (3) Premature Menopause
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.
(4) Follicle Problems
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.
Causes of Poorly Functioning Fallopian Tubes
Tubal disease 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,
with certain procedures having success rates up to 65%. The main causes of tubal damage include:
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.
(2) Abdominal Diseases
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.
(3) Previous Surgeries
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.
(4) Ectopic Pregnancy
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.
(5) Congenital Defects
In rare cases, women may be born with tubal abnormalities, usually associated with uterus irregularities.
Approximately 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 minimal endometriosis.
(1) Other variables that may cause infertility in women:
- At least 10% of all cases of female infertility are caused by an abnormal uterus. Conditions such as fibroid, polyps,
- Congenital abnormalities, such as septate uterus, may lead to recurrent miscarriages or the inability to conceive.
- Approximately 3% of couples face infertility due to problems with the femaleís cervical mucus. The mucus needs to
and adenomyosis may lead to obstruction of the uterus and Fallopian tubes.
be of a certain consistency and available in adequate amounts for sperm to swim easily within it. The most common
reason 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.
- Diet and Exercise
Optimal reproductive functioning requires both proper diet and appropriate levels of exercise. Women who are significantly overweight or underweight may have difficulty becoming pregnant.
Cigarette 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.
Alcohol intake 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.
Drugs, such 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.
- Medical Treatments and Materials
- Ethylene Oxide
- Dibromochloropropane (DBCP)
Exposure to 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.
Repeated exposure 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 problems.
A chemical 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.
Handling the 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.