Ovulatory disorders are a common cause
of infertility. Ovulation
is controlled by complex interactions between numerous
endocrine hormones including FSH, LH, estradiol, progesterone
and others. Imbalances in these hormones, or alterations
in the “feedback mechanism”, can prevent
ovulation, or cause it to be irregular.
Clomid is often used to treat anovulation (lack
of ovulation) and if it does not work, injectable
drugs such as FSH
are employed. Injectable fertility drugs are often
combined with intrauterine
In the ovary, FSH and LH provide a
signal for the development of eggs. As egg development
occurs, the hormones estrogen and inhibin, produced
by the ovary, provide negative feedback to the hypothalamus
This feedback causes the production of FSH and LH
to decrease. In the failing
ovary, (pre-menopausal) estrogen and inhibin levels
are low; the negative feedback is inhibited; and FSH
and LH levels may be high, signifying imminent ovarian
The hypothalamus is an extremely sensitive part of
the human brain, especially in females. Changes in
diet, excessive weight gain or loss, stress, excessive
exercise, emotional upheaval, and even alterations
in the light/dark cycles may alter its function. These
alterations affect the GnRH pulses and hence pituitary
function with alteration in the secretion of the hormones
FSH and LH.
These changes affect ovarian function with alterations in the production of estrogen, which prepares the uterus to accept an embryo, and progesterone, the hormone of the luteal phase, which is important in maintaining a pregnancy. Thyroid hormone balance is also extremely important to the overall functioning of this system.
Because of the hormonal changes discussed above, a female undergoes a monthly menstrual cycle. In the first half of the cycle, (proliferative phase), the lining of the uterus is developed so that an embryo can implant. This is the estrogenic phase. The second half of the cycle is characterized by the secretion of progesterone (secretory phase) to maintain the lining of the uterus.
Ovulation is the event that occurs between the proliferative and secretory phases, and is usually mid cycle. At the end of the secretory phase (which usually lasts fourteen days), menstruation (shedding of the lining of the uterus) occurs if there is no pregnancy.
The hormonal events in a normal menstrual cycle are complex. FSH is secreted from the pituitary gland causing the ovaries to produce estrogen. Just before ovulation, the hormone LH is released from the pituitary gland, triggering an ovulatory response in the ovary. (This is a hormone measured in ovulation prediction kits and is in the blood stream for a short time).
Many conditions can cause irregular
ovulation including hyperprolactinemia.
This condition is caused by a tumor (usually benign)
located on the pituitary gland. Treatment with the
drug Parlodel is often very effective.
In most cases, ovulation is effectively established using fertility medications unless there is ovarian failure due to age or other causes.
The uterus must be normally
shaped and free of obstructions, such as polyps or fibroids.
Large obstructions can interfere with embryo implantation
and normal fetal development. The uterus can be damaged
by pelvic inflammatory disease, previous surgery, endometriosis,
or some women are born with a malformed uterus.
A skilled reproductive surgeon,
like Dr. Kustin, can often surgically
repair the uterus. If the damage is severe, a surrogate
mother may be required. A surrogate is a woman who carries
the couples child ,produced by an IVF cycle, to term an
The lining of the uterus is known as the endometrium and it is capable of rapid cell growth and division. During the menstrual cycle, progesterone and estrogen stimulate the endometrium to thicken and become more vascular. This development is necessary to support the developing fetus. Poor endometrial development can often be treated with additional progesterone.