There are many types of gonadotropins
used alone or in combination for ovulation induction. They include
hMG (human Menopausal Gonadotropin, Pergonal®, or Humegon™),
hFSH (Human Follicle stimulating Hormone, Metrodin®), and hCG
(human Chorionic Gonadotropin, Profasi®, APL®, or Pregnyl®).
During the use of these drugs careful monitoring is required to
minimize the risk of side effects, discussed below.
- Ovarian Hyperstimulation (OHSS). Occurring
in 1 to 5 percent of cycles, the chance of OHSS is increased in
women with polycystic ovarian syndrome and in conception cycles.
When sever, it can result in blood clots, kidney damage, ovarian
twisting (torsion), and chest and abdominal fluid collections.
In severe cases, hospitalization is required for monitoring but
the condition is transient, lasting only a week or so. Occasionally,
drawing fluid out of the chest or abdominal cavity helps. The
best prevention is to not give hCG to induce ovulation at the
end of an overly vigorous stimulation cycle.
- Multiple Gestation. Up to 20 percent
of pregnancies resulting from gonadotropins are multiple, in contrast
to a rate of 1 to 2 percent in the general population. While most
of these pregnancies are twins, a significant percentage are triplets
or higher. High order multiple gestation pregnancy is associated
with increased risk of pregnancy loss, premature delivery, pregnancy
induced hypertension, hemorrhage, and other significant maternal
complications.
- Ectopic (Tubal Pregnancies). While
ectopic pregnancies occur 1 to 2 percent of the time, in gonadotropin
cycles the rate is slightly increased at 1 to 3 percent. These
can be treated with medicine or surgery. Combined tubal and intrauterine
pregnancies (heterotropic pregnancies) occasionally occur with
hMG and need to be treated with surgery.
- Birth Defects. The rate of birth defects
after gonadotropin cycles is no higher than in the general population,
at 2 to 3 percent. Furthermore, these children are developmentally
no different than their peers.
- Adnexal Torsion (Ovarian Twisting).
Less than 1 percent of the time, the stimulated ovary can twist
on itself, cutting off its own blood supply. Surgery is required
to untwist or even remove it.
- Gonadotropins and Ovarian Cancer.
The risk of ovarian cancer seems in part related to the number
of times a woman ovulates. Infertility increases this risk; birth
control pill use decreases it. Controversial data exists that
associate ovulation stimulation drugs like gonadotropins to the
risk of future ovarian cancer. While research is underway to help
clarify this issue, the careful use of gonadotropins is still
reasonable, especially considering that pregnancy and breast feeding
reduce cancer risk.
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