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Vitro Fertilization (IVF)
In vitro fertilization
(IVF) literally means "fertilization outside of the body" compared
to in vivo fertilization which is "fertilization within the body".
IVF has made it possible for millions of infertile couples to create healthy
genetically related children.
The IVF process is
summarized as follows: 1) the female's ovaries are stimulated to recruit many follicles each of which contains
one egg. 2) When the eggs are mature, they are withdrawn from the follicles.
3) The eggs and sperm are combined in a Petri dish. 4) Once fertilization
occurs, the embryos are cultured in an incubator where they remain for
3-5 days. 5) When the embryologist and physician agree that the embryos
are mature, they are transferred to the uterus.
IVF was first successfully
performed in the United States at the Jones Institute for Reproductive
Medicine. This is where Dr. Muasher trained and served as the Director
of the IVF Program from 1988-2000 and Director of the Division of Reproductive
Endocrinology and Infertility (1998 -2000). IVF was initially considered
an experimental procedure by the American Medical Association; however,
new technologies and dramatically improved success rates led to removal
of this designation in the early nineties.
In a natural cycle,
only one or two eggs usually develop. An IVF
cycle requires more eggs because some are invariably unhealthy or
damaged during retrieval and fertilization. Several embryos are also necessary,
as some stop growing during culturing. This is why additional follicle
stimulating hormone (FSH) is administered by injection during an IVF cycle.
FSH is naturally produced by the pituitary gland and stimulates the recruitment
and development of eggs within the ovarian follicles.
In IVF, FSH is administered
according to certain protocols usually in combination with Lupron or Antagon. These fertility drugs cause the body to dramatically reduce
the production of leutinizing hormone (LH) which is the hormone that signals
ovulation. Ovulation must not occur before the eggs are ready for retrieval
and is triggered by a timed injection of hCG, which mimics the actions
of LH. IVF protocols determine the type of medication, dosing, time of
administration, duration, and other factors. Dr. Muasher participated
in the original research that led to the IVF protocol most commonly used
by IVF clinics throughout the world.
As the follicles grow,
they cause increased production of the hormone estrogen. During a stimulated
(FSH) cycle, patients periodically come to the office for estradiol and
ultrasound measurements. This allows Dr. Muasher to monitor the development
of the follicles and protect against side effects such as "hyperstimulation"
of the ovaries.
The mature eggs are
removed from the follicles using a small needle passed through the back
of the vagina. This process is guided by ultrasound and performed under
anesthesia. As the eggs and follicular fluid are aspirated (retrieved),
they are immediately passed to the embryologist who isolates the eggs
and transfers them to a special media.
Some women cannot
produce eggs that will fertilize and develop due to many factors including
premature ovarian failure or diminished ovarian reserve. In these cases,
an IVF egg donor can be used. Egg donors
undergo the stimulation and retrieval procedures and their eggs are combined
with the partner's sperm. Egg donors receive compensation for their time
and effort.
The male supplies
sperm by masturbation on the day of the retrieval. The sperm are specially
washed and prepared for exposure to the eggs. Once the eggs are separated
into the appropriate media, sperm are added and fertilization is allowed
to occur. Thousands of sperm surround the egg; however, once one sperm
has attached to and penetrated the eggs membrane (zona pellucida) others
are prevented from entering.
When moderate to severe
male factor infertility is present,IVF with intracytoplasmic
sperm injection is often used. This procedure involves the insertion
of a single sperm directly into the egg.
Once the eggs are
fertilized, the resultant embryos are transferred to the incubator and
allowed to develop until ready for transfer, which is usually from 3 to
5 days. In younger women 5-day embryos (blastocysts) are used because
they have a greater probability of survival and fewer need be transferred
so as to decrease the risk of multiple pregnancies.
The couple returns
to the clinic on the day of transfer and the embryos are transferred to
the uterus using a small catheter in a painless procedure which only takes
a few minutes. The female is advised to rest for 24 hours.
IVF
is often used as a first line treatment for tubal disease, moderate
to severe male factor, in women of advanced age, and endometriosis. Most
women become pregnant using less advanced technologies such as medication
and intrauterine insemination.
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