Many couples faced with infertility are still
unable to become pregnant after first line therapy such as
ovulation induction, intrauterine insemination, or reproductive
surgery. For these couples, the logical next step is to explore
the Assisted Reproductive Technologies (ART).
These treatments include In Vitro Fertilization and other
assisted laboratory techniques designed to improve
fertilization.
The following explanation is meant to
simplify that occurs during various stages of IVF
Definitions
- Ovarian Follicle - a small, fluid-filled structure in
which eggs develop
- Oocyte - an egg
- Embryo - a fertilized egg that has undergone division
cleavage
Stage I : Ovarian Follicle Development through Controlled
Ovarian Stimulation
Rotunda - Hygeia uses fertility drugs that simulate the female partner, natural
hormones to develop several normal follicles in the ovaries
These medications are:
- Clomiphene Citrate also called Siphene® or
Ovofar®
- Menogon (HMG), a 50:50 mixture of FSH and LH hormonal
administered intramuscularly
- Puregon® (POFSH): administered subcutaneously
- Gonal-F (RecFSH)
Any excess Oocytes that fertilize and develop into embryos at
fertilization may later be stored through cryopreservation.
Follicular growth, development, and maturity
are evaluated through frequent hormone monitoring and by
ultrasounds. Typically, the hormones estradiol, luteinizing
hormone, and progesterone are measured through blood tests to
evaluate ovarian response. Ultrasound is used several times
during a cycle to measure accurately follicular growth and size.
These steps allow the physician team to
modify the treatment in some cases and to stop the cycle if the
response to stimulation is not satisfactory. Once follicular
maturation is achieved, the patient receives an intramuscular
injection of human chorionic gonadotropin (hCG), which triggers
oocyte maturation and ovulation. Oocyte retrieval is performed
approximately 36 hours later. In some the physician may elect to
withhold the hCG injection and wait for spontaneous ovulation,
referred to as a spontaneous LH hormone surge.
Stage II.- Embryo Retrieval through
Puncture/Aspiration
If the last hormone blood test and ultrasound evaluation
indicates healthy growth of follicles, then aspiration of mature
follicles takes place. The physician locates each
follicle through ultrasonic guidance and carefully aspirates
them.
To accomplish this, a needle is inserted (under IV sedation)
through the vaginal wall into the ovaries using ultrasound to
locate each follicle. The follicular fluid is drawn up into a
test tube to obtain the eggs. Although patients are given pain
medications intravenously and are carefully monitored by an
anesthesiologist, some women may experience some discomfort
during the procedure. Generally, the oocyte (egg) retrieval
takes 30-45 minutes. Patients are usually discharged home within
a couple of hours after the retrieval
The contents of the follicles are immediately taken to the
IVF lab. Patients usually recover for one to two hours following
Oocyte retrieval and are then discharged. Progesterone
supplementation initiated from the day of the retrieval.
Stage III.- Oocyte Culture, Insemination,
and Fertilization
In the IVF laboratory, follicular fluid is examined under a
microscope to locate all eggs, which are then incubated in a
special media. Generally, semen collection occurs at about the
time of the egg retrieval but, in some cases, may be several
hours later. The are then added to the eggs in culture, here
fertilization occurs. Any resulting embryos are stored in the
incubator. and maintained in culture until the time of embryo
transfer and/or cryopreservation
Stage IV.- Embryo Transfer
Usually, transfer of the embryos takes place on day two to three
post retrieval. The embryos are examined under the microscope
and carefully aspirated to a thin transfer catheter. The loaded
catheter introduced into the uterus through the cervix where the
embryos are placed. This procedure takes a few minutes and does
not require anesthesia. The physician administers a mild
sedative to provide complete relaxation of the cervix and
prevent cramping. The maximum number of embryos to be
transferred at one time are 3-4.
After the transfer, the patient rests for two hours prior to
discharge and complete bed rest for four days is required. On
the sixth day following the transfer, the patient returns for a
progesterone evaluation. Twelve days after the embryo transfer,
a serum base pregnancy test is taken. During this period,
patients are advised perform light activity and remain in
contact with the Center. If pregnancy does not occur, the our
team reviews the IVF cycle and make specific recommendations for
follow-up. The patient will speak with the clinical staff to
review and if necessary, to discuss other options.
Cryopreservation
Embryos of sufficient quality that are not transferred can be
cryopreserved. The embryologist will select embryos that are
suitable for freezing. Embryos that are ideal for freezing have
blastomeres of equal size and display minimal or no
fragmentation.
A Word of Caution: There is
approximately a 68% chance of survival following the
cryopreserved embryos. The quality of embryos undergoing
cryopreservation is a major determinant of survival. Depending
stage of embryo development, frozen embryos are thawed for 2
days before the transfer. The patient is informed of survival of
the thawed embryos and posted for a frozen thawed embryo
transfer (FET).
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Intracytoplasmic Sperm Injection (ICSI):
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- A micromanipulation procedure where a single sperm is injected into the
egg to enable fertilization with very low sperm counts or with non-motile
sperm.