Assisted reproductive technologies are medical treatments to overcome infertility; many infertile couples will receive though ART treatments such as medications to correct ovulatory difficulties or surgery to correct anatomical problems. For some couples, the solution may require more involved medical procedures. These are several specialized treatments designed to increase the number of eggs or sperm, or bring them combine together, thus improving the likelihood of pregnancy. ART offers hope to couples who are unable to achieve pregnancy through other approaches.
The most common type of ART is in vitro fertilization; during IVF, eggs and sperm are mixed in a laboratory dish to fertilize, and some of the fertilized eggs (zygotes) are then transferred to the woman's uterus. IVF is fertilization of eggs outside the body under laboratory conditions similar to those inside the body. The procedure is performed with sedation on an outpatient basis. Under the guidance of either laparoscopy or ultrasound, a needle is used to retrieve the maturing eggs from the ovaries. Motile sperm are collected from the man's semen and washed. The sperm and eggs are then combined in culture fluid in small dishes, which are placed in a specialized incubator. This maintains an environment as close as possible to normal body conditions while fertilization occurs. Following fertilization, embryos are observed for cell division. Developing embryos are transferred to the uterus. Extra embryos may be cryopreserved (frozen).
Other types of assisted reproductive technologies include:
Intracytoplasmic sperm injection (ICSI), the injection of a single sperm into an egg. The fertilized egg is then placed in the woman's uterus or fallopian tube. Used with in vitro fertilization, ICSI is often a successful treatment for men with impaired sperm. Intracytoplasmic sperm injection (ICSI) is a technique where a single sperm is injected into the egg by piercing the shell of the egg. ICSI can result in fertilisation rates of 55 to 70% and pregnancy rates ranging from 20 to 35%. This technique can achieve pregnancies even when only a few sperm can be found in the ejaculate. The sperm are collected from the ejaculate of the man or alternatively in lower numbers from the testis from a biopsy. The female partner is given fertility drugs to help to produce a number of eggs that are then removed by surgery. The process of injecting a single sperm into an egg is then carried out.
Gamete intrafallopian transfer (GIFT), which involves collecting eggs from the ovaries, then placing them into a thin, flexible tube with the sperm. This is then injected into the woman's fallopian tubes, where fertilization takes place. Gamete intrafallopian transfer is the placement of sperm and eggs into the fallopian tube. This transfer has generally been done by laparoscopy. The average delivery rate per retrieval for GIFT in 1994 was 28.4%, compared with 21.2% for IVF. Because IVF is less invasive, programs with IVF rates close to, or exceeding, the national average for GIFT are likely.
Zygote intrafallopian transfer (ZIFT), which combines IVF and GIFT. Eggs and sperm are mixed outside of the body. The fertilized eggs (zygotes) are then returned to the fallopian tubes, through which they travel to the uterus. The placement of fertilized oocytes (ZIFT) or cleaving embryos (tubal embryo transfer or TET) into the fallopian tubes allows fertilization to be confirmed, while taking advantage of the tubal environment for part of the early development of the embryo. The success rates for these two procedures should, theoretically, be higher than that of IVF.
Embryo cryopreservation. Cryopreservation (freezing) of fertilized oocytes is a service offered to patients when, as a result of participation in an IVF procedure, more fertilized oocytes are available than our physicians recommend be transferred in the IVF cycle. If the initial IVF attempt does not result in a pregnancy these cryopreser
Answered by
Rajib Gurung
, an ibibo Master,
at
12:17 AM on November 03, 2007
