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In Vitro Fertilization



Review Patient Information Fact Sheets from the American Society for Reproductive Medicine.

In Vitro Fertilization (IVF)

IVF has given hope to thousands of couples who otherwise had no chance of conceiving a genetically related child. IVF was first successfully performed by Dr.s' Steptoe and Edwards in England and later in the United States at the Jones Institute for Reproductive Medicine. IVF was considered experimental by the American Medical Association for many years; however it is now an excepted first line treatment for many of the conditions that cause infertility.

"In vitro" literally means "outside of the body" which describes where fertilization occurs in IVF. The female undergoes a "stimulation cycle" to cause the development and maturation of multiple eggs. The stimulation cycle involves the administration of gonadotropins (FSH and or HMG) which acts directly upon the ovaries.

The female self administers daily injections of gonadotropins and makes regular visits to the office during the stimulation cycle to monitor follicular development and check the estrogen level (estradiol) in the blood. The size of the follicles is measured using transvaginal ultrasound and development (quality and size) is accessed using measurements of the hormone estradiol.

In an IVF cycle, timing is critical since the eggs must be retrieved and embryo(s) transferred at the appropriate time. The female's cycle is controlled using various medications. Antagon or Lupron are given to "down regulate" the female's pituitary gland (in the brain) according to specific protocols. These medications dramatically lower (Lupron) or block (Antagon) the production of gonadotropin releasing hormone (GnRh) which stimulates the production of FSH and luteinizing hormone (LH). Since the drugs stop the production of FSH, it must be given by injection to stimulate the development of multiple eggs.

In a natural cycle, LH levels rise dramatically to trigger ovulation once the eggs are mature. GnRH blocks this surge in an IVF cycle so that ovulation does not occur until triggered with an injection of hCG. If ovulation were to occur early, the IVF cycle would be "lost" since the eggs could not be retrieved.

Some women cannot produce adequate follicles for many reasons including ovarian failure or poor ovarian reserve. These couples often use the eggs from a younger donor (typically less than 30 years old).

Once the eggs are mature, she receives an injection of hCG 35-36 hours prior to the scheduled retrieval. The patient and her partner arrive at the clinic on the day of retrieval and a sperm sample is collected. The sperm are specially washed and concentrated in preparation for exposure to the eggs.

At retrieval, (usually under anesthesia or in some cases a sedative is given) and the eggs are retrieved through the back wall of the vagina using transvaginal guided ultrasound. The aspirated follicular fluid is immediately passed to the embryologist who "separates out" the eggs and places them in a series of specially prepared fluid media.

The eggs are then transferred to a Petri dish and the sperm are introduced. One sperm will fertilize each egg resulting in embryos which contains the genetic makeup of the sperm and egg source. In many cases, intracytoplasmic sperm injection (ICSI) is used to insert one sperm directly into the egg. Preimplantation genetic diagnosis (PGD) might by employed if genetic disease is suspected.

The embryos are transferred to the carefully controlled environment of the incubator where they remain until mature, usually 3- 5 days. Five day embryos are termed blastocyst and are more likely to implant and develop.

Once the embryos mature, they are transferred to the uterus in a painless procedure lasting about ten minutes. The number of embryos transferred depends upon several factors including their quality, stage of development, and patient variables. The more embryos transferred, the greater the chance of multiple births. Progesterone is usually given to stimulate and support the development of the endometrium, which is where the embryo attaches.

IVF success rates vary by practice and are dependent upon the cause(s) of infertility, the patient's age, presence of male factor, physician and embryologist variables. The Centers for Disease control maintains IVF statistics for most programs at their Web site. It is virtually impossible to compare one center with another and the American Society of Reproductive Medicine (ASRM) speaks highly against doing so.

Be sure and visit the sections on donor egg, intracytoplasmic sperm injection, and preimplantation genetic diagnosis.

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