بنات البايولوجي بحث عن n Vitro Fertilizationا

1. In Vitro FertilizationHistory


2. In Vitro Fertilization


3. Step 2: Egg Retrieval under Ultrasound Guidance


4. Step 3: Semen Collection, Processing, and Insemination


5. Step 4: Fertilization


6. Step 5: Embryo Transfer under Ultrasound Guidance

In Vitro FertilizationHistory

In Vitro Fertilization Pre-Embryo Transfer (IVF-ET) is a fertility procedure which first succeeded as recently as 1978 by Dr. Edwards (an embryologist) and Dr. Steptoe (a gynecologist) in England. Since then the technology has been further refined and developed by physicians and embryologists, with over 20,000 babies born worldwide.
The possibility of a continuing pregnancy being achieved by IVF has improved from practically nil to one chance in 4 to 6 at IVF centers worldwide.
The possibility of a pregnancy being achieved for any one patient cannot be predicted, as it depends on many variables - such as age and the reproductive health of both the wife and the husband. Although the chance of success varies from case to case, a thorough evaluation is required to predict the probability of pregnancy in any given situation.
First developed by Patrick C. Steptoe and Robert G. Edwards of Great Britain (where the first "test-tube baby" was born under their care in 1978), the technique was devised for use in cases of infertility when the woman's fallopian tubes are damaged or the man's sperm count is low. It is also used to enable prospective parents with other reproductive problems (e.g., inability to produce eggs, poor sperm quality, or endometriosis) to bear a child. In embryo donation (also called embryo adoption), frozen embryos that are not needed by the mother are donated for implantation to a woman or couple who are infertile but wish to have, and are capable of bearing, children. The use of in vitro fertilization has resulted in the birth of more than 500,000 babies. Nevertheless, the technique has raised legal, ethical, and religious issues, including concerns regarding legal custody of frozen embryos following divorce and questions regarding the appropriateness of the procedure posed by the Roman Catholic Church and other institutions.

In Vitro Fertilization

In simplest terms, the IVF procedure involves stimulating the woman's ovaries with medication, to produce multiple eggs. First, the eggs are removed by a needle through the vagina while the woman is placed under a light anesthesia. Next, the man's sperm and the woman's eggs are combined in the laboratory, typically in a Petri dish. The resultant embryo is then implanted into the woman's uterus through the cervix in hopes of achieving a successful pregnancy. Usually two to four embryos are implanted each time IVF is performed (called a cycle). Results of IVF vary by the woman's age, reason for performing IVF, and the egg quality.
Initially developed in 1978 for women with blocked, damaged, or missing fallopian tubes, in-vitro fertilization (IVF) is now used to overcome infertility caused by endometriosis, male factor issues, sperm antibodies, ovulatory problems, or other unexplained reasons. In the United States, more than 17,000 healthy babies are born each year through successful IVF procedures.
In Vitro fertilization (IVF) is best described in five steps:
Step 1 - Ovarian stimulation with medication
Step 2 - Egg retrieval under ultrasound guidance
Step 3 - Semen collection
Step 4 - Fertilization
Step 5 - Embryo transfer under ultrasound guidance
Step 1: Ovarian Stimulation with Medication
Rather than a single egg normally developing each month, various medications are used to stimulate the ovaries to produce multiple mature eggs.

Step 2: Egg Retrieval under Ultrasound Guidance

Eggs may be recovered by ultrasound-directed procedures, under sedation. Ultrasound allows for accurate aspiration of the egg. We guide a needle into each follicle and aspirate its contents, then the eggs are transferred to a sterile container to await fertilization. The process is repeated until all the mature follicles have been aspirated.
We monitor the ovarian response and time the administration of Human chorionic gonadotropin (hCG), which causes the release of the egg in a woman like Luteinizing Hormone (LH) does in a normal cycle.

Step 3: Semen Collection, Processing, and Insemination

Shortly before or after the egg retrieval, a semen sample will be collected. The semen sample is then processed to isolate the strongest, most active sperm. Thousands of these sperm will then be placed with each mature egg. For partners who are concerned about producing a specimen on demand or who may not be available at the time of egg retrieval, a semen specimen is frozen several weeks before the egg retrieval.

Step 4: Fertilization

A semen sample is obtained from the male partner and processed. Once the eggs are retrieved, many prepared sperm are placed with an egg in a laboratory dish and allowed to incubate at body temperature. After approximately 48 to 72 hours, if the eggs have successfully fertilized and are growing normally, they are then transferred to the uterus. This is called embryo transfer.
If there are issues with sperm quality, then single sperm injection may be done using Intracytoplasmic Sperm Injection (ICSI).

Step 5: Embryo Transfer under Ultrasound Guidance

Embryo transfer is performed without anesthesia with the help of ultrasound. The embryos are placed in a catheter for transfer into the uterus. The use of ultrasound assures a more precise placement of the embryo.