In vitro fertilization is an option for many couples who cannot conceive through conventional therapies. In IVF, fertilization occurs outside the woman's body. The woman's eggs and the man's sperm are united in the laboratory. Once fertilization occurs, the early embryo(s) are transferred to the woman's uterus.
Eligibility Criteria: IVF is an option for couples who have tried unsuccessfully to conceive or for whom other treatments have failed. Because IVF can be an emotionally and physically exhausting procedure, it is important for each couple to evaluate and understand the RBA program in order to determine its appropriateness.
IVF was initially developed to help women conceive who had blocked, damaged, or absent fallopian tubes. Other eligible patients are those with infertility due to a condition not responsive to conventional therapy, including one or more of the following:
- Tubal blockage or failed tubal reversal
- Cervical factor
- Pelvic adhesions
- Male factor
- Unexplained infertility/ failed conventional therapy
- Genetic testing (PGD) for inheritable diseases
- Genetic testing (PGD) for possible reasons for multiple miscarriages
To be considered for IVF, a woman must either have a uterus capable of carrying a child, or a compassionate gestational carrier. For optimal results, the woman should not be more than twenty percent over her ideal body weight. We consider and evaluate women between the ages of 40-43 for IVF on an individual basis based on previous testing, such as FSH levels and/or responses to gonadotropin therapy.
Cycle Monitoring: To begin the process of IVF, the woman is given fertility drugs to stimulate egg production and control the timing of ovulation. This helps maximize the number of eggs produced, thereby increasing the chance that at least one will be fertilized, and will implant itself in the uterus. Frequent blood tests to monitor hormone levels and ultrasounds to monitor follicle development are required. Stimulation protocols may vary depending on multiple factors.
Egg Retrieval: The eggs are harvested primarily through a transvaginal ultrasound-guided procedure. The ultrasound-guided egg retrieval is performed on an outpatient basis with monitored I.V. sedation. Recovery from the sedation requires thirty minutes. The patient is discharged from the surgery center with instructions to rest for the remainder of the day.
Once the eggs are retrieved and the sperm sample collected, they are immediately given to our embryology laboratory for incubation. Our IVF lab is located adjacent to our operating room. The man's semen is specially prepared in order to select the most viable sperm. In conventional IVF, the sperm are then placed together with the eggs in an incubator for 12-18 hours to allow for fertilization. When sperm quality is compromised, the eggs are inseminated with a single sperm by means of a micromanipulation procedure known as ICSI (intracytoplasmic sperm injection). This may also be used on half of the eggs to enhance fertilization in some circumstances. Following normal fertilization, early embryonic development is closely observed on a daily basis.
Embryo Transfer: Within 72 hours after egg retrieval, the embryos are generally ready to be transferred into the woman's uterus through a thin tube, or catheter, gently inserted through the cervix. This is a non-surgical procedure performed under ultrasound guidance with no need of sedation. The woman may wish to rest for the remainder of the day in order to maximize the chance for success. About ten to twelve days following the embryo transfer, the woman's blood is drawn and tested to determine if pregnancy has occurred.
Intracytoplasmic Sperm Injection (ICSI)
What is ICSI?
ICSI (intracytoplasmic sperm injection) was first developed at the Brussels Free University in Belgium by a team that included Dr. Peter Nagy, who is now the Scientific and Laboratory Director of Reproductive Biology Associates. RBA became the first IVF center in the U.S. to achieve a pregnancy through ICSI.
ICSI involves injecting a single sperm directly into the cytoplasm of a mature egg (oocyte) using a glass needle (pipette) thus bypassing any barriers to fertilization. ICSI is currently the most successful form of micromanipulative assisted fertilization available for male factor infertility.
Reasons for ICSI:
- Sperm completely absent from the ejaculate (azoospermia)
- Sperm present in low concentrations (oligospermia).
- Poor sperm motility (asthenospermia)
- Poor sperm morphology (teratospermia)
- Sperm retrieved by surgical techniques (for example TESA, TESE)
- Problems with sperm binding to and penetrating the egg
- Antisperm antibodies
- Previous failed or poor fertilization
- Unexplained infertility
- Frozen sperm limited in quantity
- If preimplantation genetic diagnosis (PGD) is being used to screen embryos for a specific genetic disorder
The ICSI Procedure:
The process is performed on an inverted microscope at a magnification of 200x. The microscope is equipped with a warming stage to maintain a temperature of 37ºC and two micromanipulators moved hydraulically by joystick controllers. Using these tools, precise movements can be made to microtools which hold the oocyte and sperm.
The oocyte is held in place by suction on a holding pipette which is a little smaller in diameter than the oocyte. Sperm are injected using a small sharp injection pipette with an internal diameter of 5 microns, just a little larger than the width of a sperm.
A small portion of prepared sperm is added to a solution of polyvinyl pyrollidone which is viscous and slows down forward progression, making individual sperm easier to visualize and aspirate. Morphologically normal sperm are selected for injection, and then immobilized by rubbing the tails with the injection pipette. The immobilized sperm are sucked up into the injection pipette.
Oocytes oriented in such a way as to avoid injection in the area of the nucleus are held in place and a single sperm is injected into each oocyte. Once this is achieved the oocytes are returned to the incubator. Fertilization is assessed the following morning, seventeen to nineteen hours after ICSI.
Because ICSI has a history of being so reliable, we may suggest ICSI for some of your eggs even if the sperm quality looks good. It is very common for us to recommend that half of your eggs receive ICSI and the others undergo conventional IVF. We may also suggest genetic screening for patients with very low sperm counts or missing vas deferens as this can indicate mutations that make them prone to have children with cystic fibrosis.
Intracytoplasmic Sperm Injection (ICSI)
Freezing, Thawing and Lysed Cell Removal.
The IVF stimulation will often produce more eggs and embryos that are needed to be transferred. Freezing these excess embryos can provide couples with extra chances of achieving a pregnancy without having to repeat ovarian stimulation. The embryos are stored in liquid nitrogen at -196ºC (-320 °F) where they can be kept indefinitely. This process can be fairly harsh on the embryos and not all of the cells or embryos survive. Dr. Peter Nagy, RBA's scientific director, is part of a team pioneering a new technique that has been shown to dramatically increase the implantation potential of embryos that have been damaged by thawing. The technique known as Lysed Cell Removal (LCR) has now been implemented at RBA and is giving improved results. It works by making a small hole in the zona pellucida with acid or laser (use of a laser is still experiemental at this stage and currently part of an RBA study) then removing the cells that are damaged by freezing which are thought to either disrupt the development of the embryo or produce negative factors as they degenerate. The video below shows this process more clearly.
Lysed Cell Removal
Lysed cell removal, in pictures.
|1. The embryo is held securely in place with a glass holding pipette.
||2. A small hole is made in the zona pellucida with acid or a laser.
||3. The lysed (dead) cell is removed with gentle suction.
Blastocyst Culture and Transfer
In most IVF cycles at Reproductive Biology Associates the embryos are transferred on day 3, at around the 8 cell stage. We have found that this gives excellent success rates and limits the time the embryos are outside the body. In some cases however, we may recommend a blastocyst transfer. A blastocyst is is an embryo that has developed so that by day 5 it has turned into a hollow ball of cells, and is ready to expand, hatch out of the zona pellucida and implant into the uterus.
Advantages of blastocyst transfer
- Blastocysts that are transferred on day 5 synchronize with the time that embryos will usually reach the uterus in a natural conception. The uterine environment is quite different to that of the fallopian tubes and as the embryos are transferred to the uterus, it is thought it could be an advantage to wait until the blastocyst stage for this reason.
Embryos that reach the blastocyst stage have proven themselves to have a strong developmental potential, in addition using our grading system we can select the best blastocysts to transfer and hence we will not need to transfer as many embryos. Blastocyst transfers can help to reduce multiple order pregnancies.
Disadvantages of blastocyst transfer
- Not all embryos make it to the blastocyst stage and one reason for this is that the culture media used so that embryos can reach this stage outside of the body is still not optimal. This means that there could be some embryos that would do better if transferred to the uterus sooner, rather then waiting until day 5.
- Fewer embryos are frozen at the blastocyst stage.
Some indications for blastocyst transfers
- Previous failure of good quality embryos to implant
- Preimplantation genetic diagnosis
- Reducing risk wish to a multiple pregnancy.