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Encyclopedia > In vitro fertilization

In vitro fertilization (IVF) is a technique in which egg cells are fertilized outside the mother's body in cases where conception is difficult or impossible through normal intercourse. "In vitro" is Latin for "in glass", referring to the test tubes.


The technique was developed in the United Kingdom by Doctors Patrick Steptoe and Robert Edwards. The first so-called "test-tube baby", Louise Brown, was born as a result on July 25, 1978 amid intense controversy over the safety and morality of the procedure.


The first in-vitro fertilization (to produce test tube baby "Durga") in India (and second in the world) was performed by a Calcutta based doctor Dr. Subhash Mukhopadhyay on October 3, 1978.


The first successful IVF treatment in the USA (producing Elizabeth Carr) took place in 1981. Since then IVF has exploded in popularity, with as many as 1% of all births now being conceived in-vitro, with over 115,000 born in the USA to date. In brief, the process involves removing ova (eggs) from the woman's body and letting sperm fertilize them in a fluid medium. The fertilized eggs are then transferred to the mother's uterus where normal development occurs. IVF is used commonly when the father's sperm count is low or the mother's fallopian tubes are blocked.


Technique

Ovulation induction agents, such as Pergonal are usually given to the mother 8-10 days before egg retrieval, as they allow larger numbers of eggs to be recovered, improving the chances of a successful fertilization. Before the development of such drugs, few eggs would be retrieved because it required careful monitoring of the mother's 'LH surge' in order to recover eggs at the right time. This also often resulted in the performing of egg retrievals in the early morning or night time because of the unpredictability of such an occurrence. As well as 'superovulation' inducing drugs, gonadotropin releasing hormone agonists carefully control the timing of retrieval by preventing any unexpected LH surges.


The eggs can be retrieved from the mother using the more common sonographic technique involving an ultra-sound guided needle piercing the vaginal wall to reach the ovaries. The follicles within each ovary are punctured and the woman's follicular fluid containing the egss is removed and placed in an incubator. Laproscopic egg recovery involves retrieval through an incision in the abdomen. This is used in women who also require a simultaneous assessment of their pelvic anatomy through a diagnostic laparoscopy.


Semen is also taken from the husband. It can be analysed using 'sperm penetration assays', in which some sperm is checked to see whether it can puncture a zone-stripped hamster egg. The sperm can also be cultured to detect bacteria which can reduce the chances of pregnancy.


The sperm and the egg are incubated together (at a ratio of about 75,000:1) in the culture media for about 18 hours. The eggs and sperm should fertilize in the usual way in this media (see fertilization), but if this is not possible, assisted fertilization techniques -- such as injecting the sperm directly into the egg using intracytoplasmic sperm injection (ICSI) techniques (see below) -- may be used. They are then passed to a special growth medium and left for 40 hours until the eggs have become pre-embryos.


The fertilized eggs are then assessed for quality. The best ones are then transferred to the woman's uterus through a thin, plastic catheter, which passes through her vagina and cervix. Often, multiple embryos are passed into the uterus to improve chances of successful pregnancy.


The mother has to wait two weeks before she returns to the clinic for the pregnancy test. During this time she can boost the chances of pregnancy by taking progesterone - a hormone that keeps the uterus lining thickened and suitable for implantation to occur.


The chances of a successful pregnancy is approximately 20 per cent for each IVF cycle.


If the procedure is unsuccessful, the mother has to be given one month for recovery before the IVF egg-extraction procedure is repeated. This may be avoided by freezing any leftover embryos in liquid nitrogen and transferring them during the natural ovulation cycle again.


Developments

Intracytoplasmic sperm injection (ICSI) is a recent development associated with IVF which allows the sperm to be directly injected in to the egg. This is used for sperm which has problems penetrating the egg and results in success rates equal to or higher than normal fertilization.


Preimplantation genetic diagnosis (PGD) can be performed on embryos prior to the embryo transfer.


Gamete intrafallopian transfer (GIFT) is a similar procedure to IVF, which place harvested eggs and sperm straight in to the fallopian tubes where it is hoped they will fertilize naturally.


Ethics

A number of controversies has emerged related to IVF. They are usually caused by people blindly applying old ideas about conception and birth without carefully considering their applicability. These old ideas evolved when the only possible way to bear a child was for a heterosexual couple to have natural sex and wait about nine months in case of pregnancy. Today, when the child can be created outside of the woman, using genetic code from more than 2 people, when homosexual couples can have children and even dead people can have children, these old ideas are no longer valid. Still, some people complain loudly about each new "unnatural" development.


Certain ethical problems have been raised primarily due to technology being developed which has enabled the extracted embryos to be frozen. This was widely publicised when a Californian couple died in a plane crash without leaving instructions on what to do with the frozen embryos they had left in an Australian clinic. This situation has been largely solved by consent agreements given by couples before they undergo the procedure.


The use of frozen embryos that are no longer needed by the mother for research (for example stem cell research) is a hotly contested issue. A lot of the problem for some people is due to the embryos being destroyed during the course of research. Some groups protest that these embryos have the right to live, whereas other scientists reply that they would have been destroyed anyway.


Another problem brought up by the use of IVF is the unconventional possibilities regarding who uses the technique. In 2001, a French woman received worldwide publicity when she posed as the wife of her brother in order to give birth to a donor egg fertilized by his sperm. Some saw this as a form of incest; others thought it prove psychologically unhealthy for the child when he learned how he was delivered; whereas other people simply couldn't see anything wrong with the situation.


The use of IVF provides a greater range of options for single people and same-sex couples wishing to have children. Although both groups already raise children, IVF makes the option much simpler and could make the option widespread. Some people object that this could give psychological problems to the child if they grow up without a mother/father role-model.


  Results from FactBites:
 
In vitro fertilisation: Definition and Much More from Answers.com (5180 words)
IVF may be an option if there is a blockage in the fallopian tube or endometriosis in the woman, or low sperm count or poor quality sperm in the man. There are other possible treatments for these conditions, such as surgery for blocked tubes or endometriosis, which may be attempted before IVF.
As in IVF, the fertilization of the eggs occurs in a laboratory dish.
IVF is a major treatment in infertility where other methods of achieving conception have failed or is preferred by the couple based on their individual circumstances.
  More results at FactBites »

 
 

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