FSH and mixed FSH/LH products):
(Gonal-F, Follistim, Menopur, Repronex, Bravelle)
Gonadotropins (pure FSH and mixtures
of FSH and LH hormones) are the primary injectable fertility
medications. For simplicity we will refer to all gonadotropins
(pure and mixtures) as FSH.
Follicle stimulating hormone (FSH) is
a fertility medication used to directly simulate the
ovaries. It occurs naturally and is released by the
pituitary gland when it is stimulated by gonadotropin
releasing hormone (GnRH). GnRH is produced by the hypothalamus
which regulates many hormones in a system called the
hypothalamic-pituitary-adrenal axis. This is discussed
in detail in our section on ovulation.
FSH was first marketed as Pergonal,
which was derived from the urine of post menopausal
women (naturally derived). Since it was a natural product,
it contained some "impurities" notably luteinizing
hormone (LH). However, many specialists believe that
the LH is needed in some patients.
Urinary FSH/LH was purified further
and marketed as Metrodin,and subsequently highly purified
and promoted as Fertinex by Serono Laboratories. The
next step was the release of Gonal-F and Follistim which
are pure FSH products. These products are a result of
genetic recombinant technology and exactly mimic the
bodies own FSH. Other LH containing FSH preparations
are available as Repronex and Menopur.
FSH's effect on the ovaries is much
more pronounced than products such as Clomid and Letrozole.
It is used primarily in assisted reproductive technologies
(IVF) cycles and controlled ovarian hyperstimulated
intrauterine (IUI) cycles.
When FSH is used in IUI cycles the patient
must be carefully monitored to prevent ovarian hyperstimulation
syndrome (OHSS) and high order multiple births. FSH
stimulates the ovaries to develop numerous eggs that
can be released simultaneously at ovulation. Many instances
of quadruplets (and more) are the result of IUI cycles
administered by non fertility specialists.
FSH is used in IVF cycles to cause the
development and maturation of multiple eggs which will
be withdrawn from the follicles at retrieval. High order
multiple births are not common in IVF cycles because
the physician controls how many embryos are placed in
FSH is administered according to patient
specific treatment protocols. IVF patients receive Lupron
or Antagon which dramatically reduces the internal production
of FSH and LH, termed
FSH is administered by injection to
cause follicular development and patients are closely
monitored via transvaginal ultrasound and measurements
of estradiol. The dosage of FSH is varied based upon
each patient's response. Once the physician judges that
the follicles are mature, an injection of human chorionic
gonadotropin (hCG) is given and retrieval is scheduled
36 hours later.
FSH can produce serious side effects
including ovarian hyperstimulation syndrome. It should
always be administered by a reproductive endocrinologist
with extensive clinical training in its use.
Organon, manufacturer of Follistim provides extensive information on infertility.