Fertility
Medications
Clomid
Clomid (clomiphene citrate)
is one of the most common fertility medications used
to regulate or induce ovulation. Clomid (50 mg tablets)
is taken orally on days 3-7 or 5-9 of the menstrual
cycle. If no follicular development occurs (with or
without ovulation), dosages can be increased by 50 mg
increments (up to 200-250 mg), Once follicular development
and ovulation has occurred, there is no advantage to
further dosage increases.
To understand how Clomid works, it is
necessary to have a basic understanding of the hormonal
feedback mechanism operating in the ovulatory cycle.
The hypothalamus is a small gland at the base of the
brain which indirectly regulates the levels of follicle
stimulating hormone (FSH), luteinizing hormone (LH)
and others via the pituitary gland. It can be thought
of as a thermostat that varies hormonal levels based
primarily upon the levels of FSH and estrogen.
Gonadotropin releasing hormone (GnRH)
is produced by the hypothalamus and travels to the pituitary
where it stimulates the production of FSH. FSH directly
stimulates the recruitment and growth of the ovarian
follicles, each of which contains an egg. If FSH levels
remain high, as is the case with injectable FSH medications,
numerous follicles will develop and mature.
As healthy follicles develop, they produce
estrogen which travels through the bloodstream to the
hypothalamus. The hypothalamus monitors the level of
estrogen and varies the production on GnRH accordingly.
High estrogen levels signal that the follicles are mature,
which causes the production GnRH to decrease thus lowering
the levels of FSH.
Clomid works by "competing"
with the estrogen receptors at the hypothalamus. It
occupies receptors that would normally "sense"
estrogen making it seem that estrogen levels are low.
This "competing" action causes the hypothalamus
to produce more GnRH with stimulates the pituitary to
increase production of FSH.
Eighty percent of patients (who do not
already ovulate) that are prescribed Clomid will ovulate
and 40 % of those patients will conceive. Once ovulation
occurs on Clomid, there is no value in increasing the
dosage.
In general, Clomid should only be used
for a maximum of six cycles, and possibly their is no
significant advantage of treating for more than 4 cycles.
Numerous studies demonstrate that if pregnancy will
occur on Clomid, seventy-five percent will occur within
three to four cycles.
There is no medical indication for taking
Clomid for longer than 6 cycles. Clomid can have side
effects and extended use is never recommended. Clomid,
or any other fertility drug, should never be administered
until the male has had a semen analysis.
When Clomid is being prescribed without
artificial insemination (IUI), and pregnancy has not
resulted after three cycles, intrauterine insemination
(IUI) may be added for the remaining three cycles to
increase the chance of pregnancy.
However, when seeing an Infertility
Specialist, it is usually recommended that FSH (injectable
fertility drugs)be used to directly stimulate the ovaries.
If the patient fails to conceive on Clomid, with IUI
after a maximum of three to four cycles, gonadotropin
(FSH) cycles with IUI will often be attempted. If a
patient fails to conceive on FSH and IUI, in vitro fertilization
(IVF) is usually the next step. Each couples treatment
protocol is different and based upon the specific cause(s)
of their infertility.
Read About: FSH , HCG
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