What is In Vitro Fertilization (IVF)?

www.ivf.net | 2008-12-08

In Vitro Fertilization (IVF) was first done successfully in United Kingdom in 1977.  Decades ago, women who suffered an ectopic pregnancy (a condition in which the fetus grows in the fallopian tube or outside of the uterus), were treated by removing the affected fallopian tube. Unfortunately, following one ectopic pregnancy the woman had a much greater chance of repeating the same ill fate most likely losing both fallopian tubes. IVF was initially developed to help women without fallopian tubes become pregnant.

While the first IVF pregnancy in 1977 was ectopic, the first IVF baby was successfully conceived in Oldham, England in 1978, resulting in the birth of Louise Brown. Since then, there have been over one million children born by means of in vitro fertilization.

The introduction of in vitro fertilization completely changed, and greatly improved, the way doctors are able to treat the most difficult cases of infertility- even those that were previously considered untreatable. While it's not a "cure all", IVF has revolutionized the world of infertility and the medical field's approach towards treating and understanding the disease. 

In Vitro fertilization denotes "the fertilization of eggs with sperm in a laboratory". There are many stages to IVF.

Ovarian Stimulation
Each woman contains thousands of sacs, which are filled with fluid, called follicles. Inside each of the follicles is an egg, called an ovum. Normally each follicle, in a typical reproductive cycle, has a single egg attached, which will inevitably reach maturity.  Each woman will be given fertility medicines to develop multiple eggs, and in order to stimulate ovulation.

The typical protocol involves the woman being administered three types of medications: a GnRH agonist or antagonist, in order to suppress the woman's natural hormones, a gonadotropin in order to stimulate follicles and egg development, and HCG to finalize egg development and to trigger ovulation. It will be up to your doctor to discuss and plan with you the protocol, timing and the exact medications, which will be used in your cycle.

In order to monitor the progress of the developing follicles, every few days the women's hormonal blood levels are checked and a pelvic ultra sound is performed. Once there are between 10 and 30 developing follicles (eggs), and they have reached their goal size, the egg retrieval process will be planned.

Oocyte Retrieval
When the follicles have reached full growth, the egg retrieval is performed with the use of a guided ultrasound.   In a doctor's office or in a surgical facility the retrieval is performed, in order to remove the eggs from the woman's ovaries. The procedure will take approximately twenty minutes and the women will most likely be given an anesthetic for her comfort.

The procedure is performed with a long ultrasound probe into the woman's vagina. Next, a special needle in conjunction with the probe passes through the side of the vagina into the woman's ovary, where each developing follicle is easily aspirated.  In general, approximately 70% of the mature eggs will fertilize. Unfortunately, because of some slow destruction along the process, the final total number of healthy embryos is often much less than the original count of eggs and follicles. 

Following the retrieval, the woman is typically asked to rest for approximately one hour, while the embryologist examines the collected eggs for their quantity as well as their quality.
Typically, the woman will be able to return to her normal routine the following day.

Sperm Collection
There is a theory that frequent ejaculation may artificially lower the sperm count. Because of this, the man will be asked to abstain from ejaculation for a minimum of forty-eight hours prior to giving his semen. But in actuality a man with a normal sperm count will not be affected, even if he ejaculates daily.  Most laboratories require the sperm specimen within a few hours after the retrieval of the woman's eggs. In order for the semen to be separated from the liquid portion, the fresh donation is immediately taken to the lab where it's washed and separated into a medium sterile amount and then concentrated into a small quantity. At this point the sperm are tested with an array of techniques to increase their ability to fertilize the egg. In order to increase the enzymes that will be needed for egg penetration and fertilization, the sperm are treated and incubated, which alters the membrane. Next, the sperm is processed in a centrifuge, which enables the laboratory to identify the most optimal quality and concentration of the sperm. 

Fertilization and Embryo Culture
In a Petri dish, the recently collected egg is combined with the most optimal sperm. This process is called fertilization, which in actuality is the entry of the sperm into the egg.  As though it would occur naturally with your own body fluids and reproductive tract, the egg and sperm are bathed in a nourishing liquid and incubated for the next three to five days. At this point the egg and sperm will be closely monitored to see which of the eggs is fertilized. Typically, fertilization takes place within a few hours. Once the egg is fertilized, it will continue to grow in the incubator, until it becomes an embryo. Contributing to to the warmth of the uterus, the embryos will continue to grow and develop in the incubator, which will be set at normal body temperature. The laboratory simply serves as a temporary womb, to insure the optimal growth of the newly formed embryos.

Note: If there is a significant male factor involved, then several hours after egg collection ICSI is performed.
Embryos that are continuing to grow and develop properly will consist of between four to eight cells, within two to three days. The development of cells will be used as a guide, to determine which of the embryos are best for transfer into the uterus. On the following day, the patients will learn their total number of healthy embryos.  Unfortunately, as stated before, the final total number of healthy embryos is often much less than the original count of eggs and follicles. Three days after the egg retrieval process, the embryos chosen for the transfer will be identified.

Note: At this point in the IVF cycle, if the patient is planning a blastocyst transfer, this step will occur on the fifth or sixth day.
Typically, the reproductive endocrinologist and the embryologist will review the quality of the embryos and discuss their recommendation regarding the number to be transferred.

Note: Embryos which are not selected for transfer, and are still considered to be good quality, may be excellent candidates for cryopreservation with liquid nitrogen. By thawing the frozen embryos and replacing them into the uterus, the patient can undergo future IVF cycles, without repeating the previous steps.

Embryo Transfer
The embryo transfer is one of the most important aspects of in vitro fertilization. Initially the doctor will require the patient to have a full bladder (48 ounces of water) for the transfer. Because your bladder sits in front of the uterus, it outlines the uterus so the physician can more clearly see the catheter, as it passes through your cervix to your uterus. It's important to note that there is a middle ground when it comes to the fullness of the bladder. Too full and the procedure could cause discomfort and not full enough, and the doctor will have difficulty seeing the catheter.  It may seem simple, but the transfer is the most crucial part of the in vitro fertilization cycle. Here is where the skill, knowledge, experience and ability of the physician is chosen will matter most. During the procedure you will be placed on the examination table, with your feet in stirrups; very much like the position you are required to take during your typical visit for your annual pap test. At this point the embryos that appear to be the most viable are transferred between two to six days after egg retrieval, by the use of ultrasound guidance.

Typically, under the direction of a transabdominal ultrasound, the embryos are replaced into the uterus by a very thin and flexible catheter, which is introduced through the vagina and the cervix and into your uterus. The lab assistant will load the embryos into the catheter, and the doctor will carefully inject the embryos into the uterus. The doctor must transfer the embryos into the optimal part of the uterine lining, with as little disturbance to the uterus and cervix as possible. Once the catheter is withdrawn, the lab assistant returns to the laboratory to examine the catheter, to make certain the embryos have been successfully transferred. Although the embryo transfer is the shortest step in the IVF procedure, the doctor will ask that each patient stay reclined for a minimum of thirty minutes to one hour.

During this time you may experience some normal abdominal pain or pelvic cramping. Once the patient has been transferred, within the next couple of days, the growing embryos should begin to implant into the patient's uterine lining.   

Post Transfer
Once transferred the patient may notice some slight vaginal discharge, which is a result of the supplies and equipment used during the procedure itself. Most physicians will ask their patients to remain on bed rest for approximately forty-eight hours. Depending on your medical history and your doctor's preference, each patient will follow the transfer with a different protocol. Most patients follow the transfer by continuing to take medication and supplements to maintain and stabilize the pregnancy. Two weeks after the transfer, the patient will undergo a blood pregnancy test. If the pregnancy test is positive, most physicians will require the patient to repeat the test every two days until the HCG levels are high enough to visualize the pregnancy sac on a transvaginal ultrasound. Three to four weeks following the embryo transfer, the beta HCG levels should be more than 2000 IU. Finally, in order to confirm the fetal cardiac activity, a follow-up ultrasound is then performed. Next the patient will be released from the reproductive endocrinologist and transferred to their obstetrician/gynecologist for prenatal care.

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