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Gonadotropins (hMG) are hormones which
function by stimulating the ovaries to produce follicles, each
of which contains an egg. The name gonadotropin, literally translates
as “gonad” which is the name for an ovary or testicle, and “tropin”
meaning to stimulate. Gonadotropins are synthesized and released
by the pituitary gland, a small gland located at the base of the
brain. The pituitary produces two different types of gonadotropins
known as luteinizing hormone (LH) and follicle stimulating hormone
(FSH), both acting on the ovaries in a coordinated fashion to
recruit and develop ovarian follicles.
Today,
gonadotropins are obtained either as a highly-purified product
from human (urinary) sources (hMG) or are the products of genetic
engineering and biotechnology (recombinant FSH). Bravelle, Repronex,
and Menopur are examples of hMG and contain FSH with variations
in the amount of LH. Gonal-F and Follistim (rFSH) are types of
genetically engineered gonadotropins. Production of these proteins
involve incorporation of the human FSH gene into a controlled
cell-line, which then produces pure FSH identical to that produced
by the human pituitary gland.
 These
medications are given by injection to stimulate the development
of follicles (fluid-filled sacs which contain the egg) either
when ovulation is not occurring naturally, when many eggs are
needed for assisted reproductive technologies (IVF), or for timing
ovulation. FSH should be administered by a trained fertility specialist to minimize potential side effects.
A treatment cycle refers to the entire process of
ovulation induction with fertility drugs, cycle monitoring, triggering
ovulation, and determination of pregnancy with a blood test. Two
types of “cycles” are intrauterine insemination (IUI) and in vitro
fertilization (IVF).
Intrauterine Insemination Cycle (IUI) - (This is
a general discussion and does not replace the physician’s and
nurses patient specific instructions. The text is for information
only.)
With the onset of menses (first day of full flow),
a baseline sonogram and blood test should be scheduled on cycle
days 2 or 3. If the baseline tests are normal, ovarian stimulation
with gonadotropins begins.
The stimulation phase of the treatment cycle typically
lasts 7-14 days. During stimulation, patients must come to our
office about every 2-3 days for additional sonograms and/or estradiol
blood tests. These tests allow the physician to evaluate the effects
of gonadotropin stimulation on the ovaries.
Different women respond to FSH at different rates,
and even the same woman may respond differently in multiple cycles.
Therefore, the FSH dosage may be increased or decreased during
the cycle. It is essential that treatment be monitored closely
to insure proper dosing and to time the “triggering” of ovulation
with human chorionic gonadotropin (hCG). This medication is given
to mimic the LH surge and stimulate ovulation 36 hours later,
at which time insemination(s) or intercourse can be scheduled.
Additional medications, such as Lupron or birth control pills,
may be employed prior to the stimulation phase.
 Gonal-F and Follistim are injected subcutaneously
into the abdomen, or thigh, and are usually “self administered”.
Both products can be conveniently administered using a “pen injection
system” supplied by the manufacturers.
Repronex, Menopur, and Bravelle can be safely given
subcutaneously although the original hMG preparations were typically
given intramuscularly. We encourage employing the subcutaneous
route to ease administration. The injections should be given at
the same time each day (within 2 hours) usually between 7:00 and
9:00 p.m. Some patients have their husband, or a friend, administer
the injections. All patients meet with our nurses for “medication
injection training”.
Pregnancy rates using IUI vary from couple-to-couple
depending upon many factors, such as age and the presence of male
factor. However, typical pregnancy rates with IUI range from 15-20%
per cycle. The incidence of multiple births is approximately 15%.
High order (>=3) multiple births are more common with IUI than
IVF. This is because the number of embryos placed into the uterus
is controlled in IVF whereas in IU I cycles, the number of eggs
ovulated, subsequently fertilized and implanted cannot be exactly
determined.
Sometimes it is possible to freeze extra embryos for use in future cycles, a procedure known as embryo cryopreservation. When using cryopreserved embryos is it not necessary to use FSH which helps control infertility treatment costs.
Gonadotropins are associated with several side effects
including ovarian hyperstimulation syndrome (1-5%), multiple gestation
(15%), ectopic (tubal) pregnancies (1-3%), ovarian torsion (<1%),
and possibly an increased risk of ovarian cancer (controversial).
Since these medications are injectable, there is a risk of infection
at the injection site referred to as cellulitis.
Ovarian hyperstimulation syndrome (OHSS) is a condition
in which there is excessive ovarian response to fertility medication
usually associated with elevated levels of estradiol. OHSS is
comprised of ovarian enlargement (multicystic) and changes in
vascular permeability leading to ascites, the abnormal presence
of fluid in the abdominal cavity. Other consequences include electrolyte
disturbances, and rarely blood clots. Severe OHSS usually occurs
only after hCG is given.
You should call us if you have any medication problems
during the cycle, particularly, if you experience dizziness, decreased
urination or weight gain of more than 5 pounds. These cysts usually
recede after 4 to 7 days, but on rare occasions, can cause serious
problems with accumulation of fluid in the abdomen, which often
requires hospitalization.
If pregnancy occurs, this condition may persist
for 2-3 weeks because the pregnancy hormone (hCG) exacerbates
hyperstimulation. Under rare circumstances, these cysts may rupture,
or the ovary may twist, possibly requiring surgery and loss of
the involved ovary. Other side effects of hMG are breast tenderness,
mood swings, and fatigue.
-See
the IUI section for an example of a specific protocol.
-See the in vitro fertilization
section for an example of an IVF protocol.
- Review the Gonadotropin
Fact Sheet
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