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In vitro fertilisation
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In vitro fertilisation

"Naked" Egg

In vitro fertilisation (IVF) is a process by which an egg is fertilised by sperm outside the body: in vitro. IVF is a major treatment for infertility when other methods of assisted reproductive technology have failed. The process involves monitoring a woman's ovulatory process, removing ovum or ova (egg or eggs) from the woman's ovaries and letting sperm fertilize them in a fluid medium in a laboratory. When a woman's natural cycle is monitored to collect a naturally selected ovum (egg) for fertilisation, it is known as natural cycle IVF. The fertilised egg (zygote) is then transferred to the patient's uterus with the intent to establish a successful pregnancy. The first successful birth of a "test tube baby", Louise Brown, occurred in 1978. Louise Brown was born as a result of natural cycle IVF. Robert G. Edwards, the physiologist who developed the treatment, was awarded the Nobel Prize in Physiology or Medicine in 2010.

The term in vitro, from the Latin meaning in glass, is used, because early biological experiments involving cultivation of tissues outside the living organism from which they came, were carried out in glass containers such as beakers, test tubes, or petri dishes. Today, the term in vitro is used to refer to any biological procedure that is performed outside the organism it would normally be occurring in, to distinguish it from an in vivo procedure, where the tissue remains inside the living organism within which it is normally found. A colloquial term for babies conceived as the result of IVF, "test tube babies", refers to the tube-shaped containers of glass or plastic resin, called test tubes, that are commonly used in chemistry labs and biology labs. However, in vitro fertilisation is usually performed in the shallower containers called Petri dishes. One IVF method, Autologous Endometrial Coculture, is actually performed on organic material, but is still considered in vitro.

Contents


Indications

IVF may be used to overcome female infertility in the woman due to problems of the fallopian tube, making fertilisation in vivo difficult. It may also assist in male infertility, where there is defect sperm quality, and in such cases intracytoplasmic sperm injection (ICSI) may be used, where a sperm cell is injected directly into the egg cell. This is used when sperm have difficulty penetrating the egg, and in these cases the partner's or a donor's sperm may be used. ICSI is also used when sperm numbers are very low. ICSI results in success rates equal to those of IVF.

For IVF to be successful it typically requires healthy ova, sperm that can fertilise, and a uterus that can maintain a pregnancy. Due to the costs of the procedure, IVF is generally attempted only after less expensive options have failed.

IVF can also be used with egg donation or surrogacy where the woman providing the egg isn't the same who will carry the pregnancy to term. This means that IVF can be used for females who have already gone through menopause. The donated oocyte can be fertilised in a crucible. If the fertilisation is successful, the embryo will be transferred into the uterus, within which it may implant.

IVF can also be combined with preimplantation genetic diagnosis (PGD) to rule out presence of genetic disorders. A similar but more general test has been developed called Preimplantation Genetic Haplotyping

Method

Theoretically, in vitro fertilisation could be performed by collecting the contents from a woman's fallopian tubes or uterus after natural ovulation, mixing it with semen, and reinserting into the uterus. However, without additional techniques, the chances of pregnancy would be extremely small. Such additional techniques that are routinely used in IVF include ovarian hyperstimulation to retrieve multiple eggs, ultrasound-guided transvaginal oocyte retrieval directly from the ovaries, egg and sperm preparation, as well as culture and selection of resultant embryos before embryo transfer back into the uterus.

Ovarian hyperstimulation

There are two current main protocols for stimulating the ovaries for IVF treatment. The long protocol involves downregulation (suppression or exhaustion) of the pituitary ovarian axis by the prolonged use of a GnRH agonist. Subsequent ovarian hyperstimulation, typically using follicle stimulating hormone (FSH), starts once the process of downregulation is complete, generally after 10 to 14 days. An IVF cycle using this protocol is known as conventional IVF.

The short protocol skips the downregulation part, and consists of a regimen of fertility medications to stimulate the development of multiple follicles of the ovaries. In most patients, injectable gonadotropins (usually FSH analogues) are used under close monitoring. Such monitoring frequently checks the estradiol level and, by means of gynecologic ultrasonography, follicular growth. Typically approximately 10 days of injections will be necessary. Spontaneous ovulation during the cycle is typically prevented by the use of GnRH antagonists that are used just during the last days of stimulation to block the natural surge of luteinising hormone (LH) and allow the physician to start the ovulation process by using medication, usually injectable human chorionic gonadotropins.

Ovarian stimulation carries the risk of excessive stimulation leading to ovarian hyperstimulation syndrome (OHSS). This complication is life-threatening and ovarian stimulation using gonadotropins must only be carried out under strict medical supervision.

Natural and Mild IVF

IVF can be performed by collecting a naturally selected egg from woman s natural menstrual cycle without the use of any drugs. It is known as natural cycle IVF.[1] The first test tube baby Louise Brown was born following natural cycle IVF. This method can be successfully used when women want to avoid taking ovarian stimulating drugs with its associated side-effects. HFEA has estimated the live birth rate to be approximately 1.3% per natural cycle IVF for women aged between 40 42.[2]

The next step-up method is called modified natural cycle IVF. In this method, medication is used for 2 4 days during woman s natural cycle to avoid spontaneous ovulation and to make the treatment more successful. As the success rates are improved it is a widely used method of natural IVF. It is particularly beneficial in women with very low egg reserve and in those whose ovaries do not respond to drugs.

Mild IVF[3] is a method where a small dose of ovarian stimulating drugs are used for a short duration during a woman s natural cycle aimed at producing 2 7 eggs and creating healthy embryos. This method appears to be an advance in the field to reduce complications and side-effects for women and it is aimed at quality, and not quantity of eggs and embryos. One study comparing a mild treatment (mild ovarian stimulation with GnRH antagonist co-treatment combined with single embryo transfer) to a standard treatment (stimulation with a GnRH agonist long-protocol and transfer of two embryos) came to the result that the proportions of cumulative pregnancies that resulted in term live birth after 1 year were 43.4% with mild treatment and 44.7% with standard treatment.[4] Mild IVF can be cheaper than conventional IVF and with a significantly reduced risk of multiple gestation and OHSS.[5] There is also evidence that the birthweights of babies are higher in women treated by natural or mild IVF compared to conventional IVF.

Egg retrieval

When the ovarian follicles have reached a certain degree of development, final maturation is induced, generally by an injection of human chorionic gonadotropin (hCG). Commonly, this is known as the "trigger shot."[6] hCG acts as an analogue of luteinising hormone, and ovulation would occur between 38 and 40 hours after a single HCG injection,[7] but the egg retrieval is performed at a time usually between 34 and 36 hours after hCG injection, that is, just prior to when the follicles would rupture. This avails for scheduling the egg retrieval procedure at a time where the eggs are fully mature. HCG injection confers a risk of ovarian hyperstimulation syndrome. Using a GnRH agonist instead of hCG eliminates the risk of ovarian hyperstimulation syndrome, but with a delivery rate of approximately 6% less than with hCG.[8]

The eggs are retrieved from the patient using a transvaginal technique called transvaginal oocyte retrieval, involving an ultrasound-guided needle piercing the vaginal wall to reach the ovaries. Through this needle follicles can be aspirated, and the follicular fluid is handed to the IVF laboratory to identify ova. It is common to remove between ten and thirty eggs. The retrieval procedure takes about 20 minutes and is usually done under conscious sedation or general anaesthesia.

Egg and sperm preparation

In the laboratory, the identified eggs are stripped of surrounding cells and prepared for fertilisation. An oocyte selection may be performed prior to fertilisation to select eggs with optimal chances of successful pregnancy. In the meantime, semen is prepared for fertilisation by removing inactive cells and seminal fluid in a process called sperm washing. If semen is being provided by a sperm donor, it will usually have been prepared for treatment before being frozen and quarantined, and it will be thawed ready for use.

Fertilisation

The sperm and the egg are incubated together at a ratio of about 75,000:1 in the culture media for about 18 hours. In most cases, the egg will be fertilised by that time and the fertilised egg will show two pronuclei. In certain situations, such as low sperm count or motility, a single sperm may be injected directly into the egg using intracytoplasmic sperm injection (ICSI). The fertilised egg is passed to a special growth medium and left for about 48 hours until the egg consists of six to eight cells.

In gamete intrafallopian transfer, eggs are removed from the woman and placed in one of the fallopian tubes, along with the man's sperm. This allows fertilisation to take place inside the woman's body. Therefore, this variation is actually an in vivo fertilisation, not an in vitro fertilisation.

Embryo culture

Typically, embryos are cultured until having reached the 6 8 cell stage three days after retrieval. In many Canadian, American and Australian programmes, however, embryos are placed into an extended culture system with a transfer done at the blastocyst stage at around five days after retrieval, especially if many good-quality embryos are still available on day 3. Blastocyst stage transfers have been shown to result in higher pregnancy rates.[9] In Europe, transfers after 2 days are common.

Culture of embryos can either be performed in an artificial culture medium or in an autologous endometrial coculture (on top of a layer of cells from the woman's own uterine lining). With artificial culture medium, there can either be the same culture medium throughout the period, or a sequential system can be used, in which the embryo is sequentially placed in different media. For example, when culturing to the blastocyst stage, one medium may be used for culture to day 3, and a second medium is used for culture thereafter.[10] Single or sequential medium are equally effective for the culture of human embryos to the blastocyst stage.[11] Artificial embryo culture media basically contain glucose, pyruvate, and energy-providing components, but addition of amino acids, nucleotides, vitamins, and cholesterol improve the performance of embryonic growth and development.[12] Methods to permit dynamic embryo culture with fluid flow and embryo movement are also available.[13] A new method in development uses the uterus as an incubator and the naturally occurring intrauterine fluids as culture medium by encapsulating the embryos in permeable intrauterine vessel.[14]

Embryo selection

Laboratories have developed grading methods to judge oocyte and embryo quality. In order to optimise pregnancy rates, there is significant evidence that a morphological scoring system is the best strategy for the selection of embryos.[15] However, presence of soluble HLA-G might be considered as a second parameter if a choice has to be made between embryos of morphologically equal quality.[15] Also, two-pronuclear zygotes (2PN) transitioning through 1PN or 3PN states tend to develop into poorer-quality embryos than those that constantly remain 2PN.[16]

More advanced methods of embryo profiling may also be performed in order to optimise embryo selection, as further described in the "expansions"-section below.

Embryo transfer

Embryos are failed by the embryologist based on the amount of cells, evenness of growth and degree of fragmentation. The number to be transferred depends on the number available, the age of the woman and other health and diagnostic factors. In countries such as Canada, the UK, Australia and New Zealand, a maximum of two embryos are transferred except in unusual circumstances. In the UK and according to HFEA regulations, a woman over 40 may have up to three embryos transferred, whereas in the USA, younger women may have many embryos transferred based on individual fertility diagnosis. Most clinics and country regulatory bodies seek to minimise the risk of pregnancies carrying multiples, as it is not uncommon for more implantations to take than desired. The embryos judged to be the "best" are transferred to the patient's uterus through a thin, plastic catheter, which goes through her vagina and cervix. Several embryos may be passed into the uterus to improve chances of implantation and pregnancy.

Success rates

IVF success rates are the percentage of all IVF procedures which result in a favorable outcome. Depending on the type of calculation used, this outcome may represent the number of confirmed pregnancies, called the pregnancy rate or number of live births, called the live birth rate.

Due to advancement in reproductive technology, the IVF success rates are substantially better today than they were just a few years ago. The most current data available in the United States a 2009 summary complied by the Society for Reproductive Medicine (SART) which reports the average national IVF success rates per age group using non-donor eggs (see table below).[17]

<35 35-37 38-40 41-42
Pregnancy Rate 47.6 38.9 30.1 20.5
Live Birth Rate 41.4 31.7 22.3 12.6

The live birth rates using donor eggs are also given by the SART and include all age groups using either fresh or thawed eggs.[17]

Fresh Donor Egg Embryos Thawed Donor Egg Embryos
Live Birth Rate 55.1 33.8

In 2006, Canadian clinics reported an average pregnancy rate of 35%.[18] A French study estimated that 66% of patients starting IVF treatment finally succeed in having a child (40% during the IVF treatment at the center and 26% after IVF discontinuation). Achievement of having a child after IVF discontinuation was mainly due to adoption (46%) or spontaneous pregnancy (42%).[19]

Live birth rate

The live birth rate is the percentage of all IVF cycles that lead to a live birth. This rate does not include miscarriage or stillbirth and multiple-order births such as twins and triplets are counted as one pregnancy. The live birth rate is calculated as follows:

Number of live births Number of procedures performed (cycle start, egg retrieval or embryo transfer)

[20]

In 2006, Canadian clinics reported a live birth rate of 27%.[18] Birth rates in younger patients were slightly higher, with a success rate of 35.3% for those 21 and younger, the youngest group evaluated. Success rates for older patients were also lower and decrease with age, with 37-year-olds at 27.4% and no live births for those older than 48, the oldest group evaluated.[21] Some clinics exceeded these rates, but it is impossible to determine if that is due to superior technique or patient selection, because it is possible to artificially increase success rates by refusing to accept the most difficult patients or by steering them into oocyte donation cycles (which are compiled separately). Further, pregnancy rates can be increased by the placement of several embryos at the risk of increasing the chance for multiples.

Because not each IVF cycle that is started will lead to oocyte retrieval or embryo transfer, reports of live birth rates need to specify the denominator, namely IVF cycles started, IVF retrievals, or embryo transfers. The Society for Assisted Reproductive Technology (SART) summarised 2008-9 success rates for US clinics for fresh embryo cycles that did not involve donor eggs and gave live birth rates by the age of the prospective mother, with a peak at 41.3% per cycle started and 47.3% per embryo transfer for patients under 35 years of age.

IVF attempts in multiple cycles result in increased cumulative live birth rates. Depending on the demographic group, one study reported 45% to 53% for three attempts, and 51% to 71% to 80% for six attempts.[22]

Pregnancy rate

Pregnancy rate may be defined in various ways. In the United States, the pregnancy rate used by the Society for Assisted Reproductive Technology and the Centers for Disease Control (and appearing in the table in the Success Rates section above) are based on fetal heart motion observed in ultrasound examinations. However, some clinics may advertise pregnancy rates based on pregnancy tests which are less definitive, such as urine or blood tests for hCG. This is the rate most often published by fertility clinics because often at the time of publishing not all IVF patients have given birth.[23] The pregnancy rate is calculated as follows:

Number pregnancies / Number of procedures performed (cycle start, egg retrieval or embryo transfer)[20]

Success or failure factors

The main potential factors that influence pregnancy (and live birth) rates in IVF have been suggested to be maternal age, duration of infertility or subfertility, bFSH and number of oocytes, all reflecting ovarian function.[24] Optimal woman s age is 23 39 years at time of treatment.[25]

Stress

In a 2005 Swedish study,[26] 166 women were monitored starting one month before their IVF cycles, and the results showed no significant correlation between psychological stress and IVF outcome. The study concluded with the recommendation to clinics that it might be possible to reduce the stress experienced by IVF patients during the treatment procedure by informing them of those findings. While psychological stress experienced during a cycle might not influence an IVF outcome, it is possible that the experience of IVF can result in stress that leads to depression. The financial consequences alone of IVF can influence anxiety and become overwhelming. However, for many couples, the alternative is infertility, and the experience of infertility itself can also cause extreme stress and depression.

Other factors

Other determinants of outcome of IVF include:

Aspirin, however, was shown by a meta-analysis to not improve pregnancy rates after IVF.[31]

Complications in the IVF procedure

Possible risks may occur throughout the procedure, and depend on the specific step of the procedure. During ovarian stimulation, hyperstimulation syndrome may occur. This results in swollen, painful ovaries and some form of it (mild, moderate or severe) occurs in 30% of patients. Mild cases can be treated with over the counter medications and cases can be resolved in the absence of pregnancy. In moderate cases, ovaries swell and fluid accumulated in the abdominal cavities and may have symptoms of heartburn, gas, nausea or loss of appetite. In severe cases patients have sudden excess abdominal pain, nausea, vomiting and will result in hospitalisation. During egg retrieval, there s a small chance of bleeding, infection, and damage to surrounding structures like bowel and bladder (transvaginal ultrasound aspiration) as well as difficulty breathing, chest infection, allergic reactions to meds, or nerve damage (laproscopy). During embryo transfer, if more than one embryo is transferred there s always a risk of multiple pregnancy, infertile couples may see this is good news but there may be risk to the embryos and to the mother such as premature delivery. Ectopic pregnancy may also occur if a fertilised egg develops outside the uterus, usually in the fallopian tubes and requires immediate destruction of the fetus.

Multiple Births

The major complication of IVF is the risk of multiple births. This is directly related to the practice of transferring multiple embryos at embryo transfer. Multiple births are related to increased risk of pregnancy loss, obstetrical complications, prematurity, and neonatal morbidity with the potential for long term damage. Strict limits on the number of embryos that may be transferred have been enacted in some countries (e.g. Britain, Belgium) to reduce the risk of high-order multiples (triplets or more), but are not universally followed or accepted. Spontaneous splitting of embryos in the womb after transfer can occur, but this is rare and would lead to identical twins. A double blind, randomised study followed IVF pregnancies that resulted in 73 infants (33 boys and 40 girls) and reported that 8.7% of singleton infants and 54.2% of twins had a birth weight of < .[32]

However, despite the risks, some recent evidence suggests that twins conceived by IVF actually have a 40% decreased outcome risk for complications than spontaneous twin conceptions.[33] Experts believe that this could be due to high level of prenatal monitoring received from the moment of conception.[34]

Recent evidence also suggest that singleton offspring after IVF is at higher risk for lower birth weight for unknown reasons.

Birth defects

The issue of birth defects has been a controversial topic in IVF. Many studies do not show a significant increase after use of IVF, and some studies suggest higher rates for ICSI, whereas others do not support this finding.[35] In 2008, an analysis of the data of the National Birth Defects Study in the US found that certain birth defects were significantly more common in infants conceived through IVF, notably septal heart defects, cleft lip with or without cleft palate, esophageal atresia, and anorectal atresia; the mechanism of causality is unclear.[36]

A 2002 study, reviewing the birth records of all the IVF babies in Western Australia "has found IVF kids are twice as likely to have birth defects as normal births". The study allowed for the effects of multiple births and the mother's age. The higher incidence of birth defects "up to one year of age" included: heart defects, "chromosomal abnormalities like Down syndrome, spina bifida, gastro-intestinal abnormalities, musculo-skeletal, dislocated hips," and club feet. The IVF children also were found to have a higher incidence of lower birth weights, pre-term births, and cerebral palsy.[37]

Japan's government prohibited the use of in vitro fertilisation procedures for couples in which both partners are infected with HIV. Despite the fact that the ethics committees previously allowed the Ogikubo, Tokyo Hospital, located in Tokyo, to use in vitro fertilisation for couples with HIV, the Ministry of Health, Labour and Welfare of Japan decided to block the practice. Hideji Hanabusa, the vice president of the Ogikubo Hospital, states that together with his colleagues, he managed to develop a method through which scientists are able to remove HIV from sperm.[38]

Other risks

Another risk of ovarian stimulation is the development of ovarian hyperstimulation syndrome, particularly if hCG is used to "trigger ovulation".

If the underlying infertility is related to abnormalities in spermatogenesis, it is plausible, but too early to examine that male offspring is at higher risk for sperm abnormalities.

Behavior and socioemotional functioning of children conceived by IVF is normal overall, according to studies on 9 18-year-old IVF children.[39]

A negative pregnancy test after IVF is associated with an increased risk for depression in women, but not with any increased risk of developing anxiety disorders.[40] Pregnancy test results do not seem to be a risk factor for depression or anxiety among men.[40]

A group of Swiss researchers published a study demonstrating that healthy children conceived by "assisted reproductive technology" (ART) display generalized vascular dysfunction and that this problem does appears to be related to the ART procedure itself. [41]

[42]

[43]

Expansions

There are various expansions or additional techniques that can be applied in IVF, which are usually not necessary for the IVF procedure itself, but would be virtually impossible or technically difficult to perform without concomitantly performing methods of IVF.

Embryo profiling

In addition to the methods already mentioned in the embryo selection above, there are more advanced techniques of embryo profiling that give more information to aid in the selection of the optimal embryo.

Also, methods are emerging in making comprehensive analyses of up to entire genomes, transcriptomes, proteomes and metabolomes which may be used to score embryos by comparing the patterns with ones that have previously been found among embryos in successful versus unsuccessful pregnancies:[44]

  • In transcriptome evaluation, however, gene expression profiling studies of human embryos are limited due to legal and ethical issues.[44] An alternative or complement is gene expression profiling of cumulus cells surrounding the oocyte and early embryo, or on granulosa cells.[44] Profiling of cumulus cells can give valuable information regarding the efficiency of an ovarian hyperstimulation protocol, and may indirectly predict oocyte aneuploidy, embryo development and pregnancy outcomes, without having to perform any invasive procedure directly in the embryo.[44]
  • Proteome profiling of embryos can indirectly be evaluated by sampling of proteins found in the vicinity of embryos, thereby providing a non-invasive method of embryo profiling.[44] Examples of protein markers evaluated in such profiling include CXCL13 and granulocyte-macrophage colony-stimulating factor, where lower protein amounts are associated with higher implantation rates.[44]

Another level of opportunity can be achieved by having the evaluation of the embryo profile tailored to the maternal status in regard to, for example health or immune status, potentially further detailed by similar profiling of the maternal genome, transcriptome, proteome and metabolome. Two examples of proteins that may be included in maternal profiling are endometrium-derived stathmin 1 and annexin A2, whose down- and up-regulation, respectively, are associated with higher rates of successful implantation.[44]

The end-point of interest in the evaluation of an embryo profile is not necessarily the success rate of the pregnancy at hand, but may also be the health of the potential person as a child and adult in the future, such as in detection of inheritable diseases by preimplantation genetic diagnosis (PGD) or screening (PGS):[45]

Preimplantation genetic screening or diagnosis (PGS or PGD)

Preimplantation genetic screening (PGS) or preimplantation genetic diagnosis (PGD) has been suggested to be able to be used in IVF to select an embryo that appears to have the greatest chances for successful pregnancy. However, a systematic review and meta-analysis of existing randomised controlled trials came to the result that there is no evidence of a beneficial effect of PGS as measured by live birth rate.[46] On the contrary, for women of advanced maternal age, PGS significantly lowers the live birth rate.[46] Technical drawbacks, such as the invasiveness of the biopsy, and non-representative samples because of mosaicism are the major underlying factors for inefficacy of PGS.[46]

Still, as an expansion of IVF, patients who can benefit from PGS/PGD include:

  • Couples who have a family history of inherited disease
  • Couples who want to use gender selection to prevent a gender-linked disease
  • Couples who already have a child with an incurable disease and need compatible cells from a second healthy child to cure the first, resulting in a "saviour sibling" that matches the sick child in HLA type.[47]

PGS screens for numeral chromosomal abnormalities while PGD diagnosis the specific molecular defect of the inherited disease. In both PGS and PGD, individual cells from a pre-embryo are analysed during the IVF process. Before the transfer of a pre-embryo back to a woman's uterus, one or two cells are removed from the pre-embryos (8-cell stage). These cells are then evaluated for normality. Typically within one to two days, following completion of the evaluation, only the normal pre-embryos are transferred back to the woman's uterus. In addition, PGS can reduce the risk of multiple pregnancies because fewer embryos are needed for implantation.

Cryopreservation

Cryopreservation can be performed as oocyte cryopreservation before fertilisation, or as embryo cryopreservation after fertilisation.

The Rand Consulting Group has estimated there to be 400,000 frozen embryos in the United States.[48] The advantage is that patients who fail to conceive may become pregnant using such embryos without having to go through a full IVF cycle. Or, if pregnancy occurred, they could return later for another pregnancy. Spare oocytes or embryos resulting from fertility treatments may be used for oocyte donation or embryo donation to another woman or couple, and embryos may be created, frozen and stored specifically for transfer and donation by using donor eggs and sperm. Also, oocyte cryopreservation can be used for women who are likely to lose their ovarian reserve due to undergoing chemotherapy.[49]

The outcome from using cryopreserved embryos has uniformly been positive with no increase in birth defects or development abnormalities.[50]

Other expansions

  • Intracytoplasmic sperm injection (ICSI) is where a single sperm is injected directly into an egg. Its main usage as an expansion of IVF is to overcome male infertility problems, although it may also be used where eggs cannot easily be penetrated by sperm, and occasionally in conjunction with sperm donation. It can be used in teratozoospermia, since once the egg is fertilised abnormal sperm morphology does not appear to influence blastocyst development or blastocyst morphology.[51]
  • Assisted zona hatching (AZH) can be performed shortly before the embryo is transferred to the uterus. A small opening is made in the outer layer surrounding the egg in order to help the embryo hatch out and aid in the implantation process of the growing embryo.
  • In egg donation and embryo donation, the resultant embryo after fertilisation is inserted in another woman than the one providing the eggs. These are resources for women with no eggs due to surgery, chemotherapy, or genetic causes; or with poor egg quality, previously unsuccessful IVF cycles or advanced maternal age. In the egg donor process, eggs are retrieved from a donor's ovaries, fertilised in the laboratory with the sperm from the recipient's partner, and the resulting healthy embryos are returned to the recipient's uterus.
  • Embryo splitting can be used for twinning to increase the number of available embryos.[52]

Leftover embryos or eggs

There may be leftover embryos or eggs from IVF procedures if the woman for whom they were originally created has successfully carried one or more pregnancies to term. With the woman's or couple's permission, these may be donated to help other women or couples as a means of third party reproduction.

In embryo donation, these extra embryos are given to other couples or women for transfer with the goal of producing a successful pregnancy. The resulting child is considered the child of the woman who carries it and gives birth, and not the child of the donor, the same as occurs with egg donation or sperm donation.

Typically, genetic parents donate the eggs to a fertility clinic or embryo bank where they are preserved by oocyte cryopreservation or embryo cryopreservation until a carrier is found for them. Typically the process of matching the embryo(s) with the prospective parents is conducted by the agency itself, at which time the clinic transfers ownership of the embryos to the prospective parents.[53]

In the United States, women seeking to be an embryo recipient undergo infectious disease screening required by the U.S. Food and Drug Administration (FDA), and reproductive tests to determine the best placement location and cycle timing before the actual Embryo Transfer occurs. The amount of screening the embryo has already undergone is largely dependent on the genetic parents' own IVF clinic and process. The embryo recipient may elect to have her own embryologist conduct further testing.

Alternatives to donating unused embryos are destroying them (or having them implanted at a time where pregnancy is very unlikely),[54] keeping them frozen indefinitely, or donating them for use in research (with results in their unviability). Individual moral views on disposing leftover embryos may depend on personal views on the beginning of human personhood and definition and/or value of potential future persons and on the value that is given to fundamental research questions. Some people believe donation of leftover embryos for research is a good alternative to discarding the embryos when patients receive proper, honest and clear information about the research project, the procedures and the scientific values).[55]

History

There was a transient biochemical pregnancy reported by Australian Foxton School researchers in 1953. John Rock was the first to extract an intact fertilised egg.[56] The first pregnancy achieved through in vitro human fertilisation of a human oocyte was reported in The Lancet from the Monash University team[57] in 1973, although it lasted only a few days and would today be called a biochemical pregnancy. There was also an ectopic pregnancy reported by Patrick Steptoe and Robert Edwards in 1976. In 1977, Steptoe and Edwards successfully carried out a pioneering conception which resulted in the birth of the world's first baby to be conceived by IVF, Louise Brown on 25 July 1978, in Oldham General Hospital, Greater Manchester, UK.[58][59][60]

In October 1978, it was reported that Subash Mukhopadyay, a relatively unknown physician from Kolkata, India was performing experiments on his own with primitive instruments and a household refrigerator and this resulted in a test tube baby, later named as "Durga" (alias Kanupriya Agarwal) who was born on 3 October 1978.[61] However, state authorities prevented him from presenting his work at scientific conferences[62] and, in the absence of scientific evidence, his work is not recognised by the international scientific community.

Steptoe and Edwards were responsible for the world s second (confirmed) baby conceived by IVF, Alastair MacDonald born on 14 January 1979 in Glasgow.[63] A team led by Ian Johnston and Alex Lopata were responsible for Australia s first baby conceived by IVF, Candice Reed born on 23 June 1980 in Melbourne.[64] It was the subsequent use of stimulated cycles with clomiphene citrate and the use of human chorionic gonadotrophin (hCG) to control and time oocyte maturation, thus controlling the time of collection, that converted IVF from a research tool to a clinical treatment.

This was followed by a total of 14 pregnancies resulting in nine births in 1981 with the Monash University team. The Jones team[65] at the Eastern Virginia Medical School in Norfolk, Virginia, further improved stimulated cycles by incorporating the use of a follicle-stimulating hormone (uHMG). This then became known as controlled ovarian hyperstimulation (COH). Another step forward was the use of gonadotrophin-releasing hormone agonists (GnRHA), thus decreasing the need for monitoring by preventing premature ovulation, and more recently gonadotrophin-releasing hormone antagonists (GnRH Ant), which have a similar function. The additional use of the oral contraceptive pill has allowed the scheduling of IVF cycles, which has made the treatment far more convenient for both staff and patients.

The ability to freeze and subsequently thaw and transfer embryos has significantly improved the feasibility of IVF use.[66] The other very significant milestone in IVF was the development of the intracytoplasmic sperm injection (ICSI) of single sperms by Andr van Steirteghem and Paul Devroey in Brussels (UZ Brussel), 1992. This has enabled men with minimal sperm production to achieve pregnancies. ICSI is sometimes used in conjunction with sperm recovery, using a testicular fine needle or open testicular biopsy. Using this method, some men with Klinefelter's syndrome, and so would be otherwise infertile, have occasionally been able to achieve pregnancy.[66][67] Thus, IVF has become the final solution for most fertility problems, moving from tubal disease to male factor, idiopathic subfertility, endometriosis, advanced maternal age, and anovulation not responding to ovulation induction.

Robert Edwards was awarded the 2010 Nobel Prize in Physiology or Medicine "for the development of in vitro fertilization".[68] Carl Wood was dubbed "the father of IVF (in vitro fertilisation)" for having pioneered the use of frozen embryos.[69]

In the US, ART cycles started in 2006 resulted in 41,343 births (54,656 infants), which is slightly more than 1% of total US births.[70]

Ethics

Issues

In a few cases, laboratory mix-ups (misidentified gametes, transfer of wrong embryos) have occurred, leading to legal action against the IVF provider and complex paternity suits. An example is the case of a woman in California who received the embryo of another couple and was notified of this mistake after the birth of her son.[71] This has led to many authorities and individual clinics implementing procedures to minimise the risk of such mix-ups. The HFEA, for example, requires clinics to use a double witnessing system, where the identity of specimens is checked by two people at each point at which specimens are transferred. Alternatively, technological solutions are gaining favour, to reduce the manpower cost of manual double witnessing, and to further reduce the risk of human error.[72] Technological solutions typically involve tagging individual specimen containers with uniquely numbered RFID tags which can be identified by readers connected to a computer. The computer tracks specimens throughout the process and alerts the embryologist if non-matching specimens are identified.

Another concern is that people will screen in or out for particular traits, using preimplantation genetic diagnosis. For example, a deaf British couple, Tom and Paula Lichy, have petitioned to create a deaf baby using IVF.[73] Some medical ethicists have been very critical of this approach. Jacob Appel wrote that "intentionally culling out blind or deaf embryos might prevent considerable future suffering, while a policy that allowed deaf or blind parents to select for such traits intentionally would be far more troublesome."[74]

Current state of the industry

Many people do not oppose the IVF practice itself (i.e. the creating of a pregnancy through "artificial" ways) but are highly critical of the current state of the present day industry. Such individuals argue that the industry has now become a multi-billion industry, which is widely unregulated and prone to serious abuses in the desire of practitioners to obtain profit. For instance, in 2008, a California physician transferred 12 embryos to a woman who gave birth to octuplets (see Suleman octuplets). This has made international news, and had led to accusations that many doctors are willing to seriously endanger the health and even life of women in order to gain money. Robert Winston, professor of fertility studies at Imperial College London, had called the industry "corrupt" and "greedy" saying that "One of the major problems facing us in healthcare is that IVF has become a massive commercial industry," and that "What has happened, of course, is that money is corrupting this whole technology", and accused authorities of failing to protects couples from exploitation "The regulatory authority has done a consistently bad job. It's not prevented the exploitation of women, it's not put out very good information to couples, it's not limited the number of unscientific treatments people have access to".[75] The industry has been accused of making unscientific claims, and distorting facts relating to infertility, in particular through widely exaggerated claims about how common infertility is in society, in an attempt to get as many couples as possible and as soon as possible to try treatments (rather than trying to conceive naturally for a longer time). Indeed, there are serious concerns about the overuse of treatments, for instance Dr. Sami David, a fertility specialist and one of the pioneers of the early days of the IVF treatments, has expressed disappointment over the current state of the industry, and said many procedures are unnecessary; he said: "It's being the first choice of treatment rather than the last choice. When it was first opening up in late 1970s, early 80s, it was meant to be the last resort. Now it's a first resort. I think that's an injustice to women. I also think it can harm women in the long run."[76]

Pregnancy past menopause

Although menopause is a natural barrier to further conception, IVF has allowed women to be pregnant in their fifties and sixties. Women whose uterus has been appropriately prepared receive embryos that originated from an egg of an egg donor. Therefore, although these women do not have a genetic link with the child, they have an emotional link through pregnancy and childbirth. In many cases the genetic father of the child is the woman's partner. Even after menopause the uterus is fully capable of carrying out a pregnancy.[77]

Same-sex couples, single and unmarried parents

A 2009 statement from the ASRM found no persuasive evidence that children are harmed or disadvantaged solely by being raised by single parents, unmarried parents, or homosexual parents. It did not support restricting access to assisted reproductive technologies on the basis of a prospective parent's marital status or sexual orientation.[78]

Ethical concerns include reproductive rights, the welfare of offspring, nondiscrimination against unmarried individuals, homosexual, and professional autonomy.[78]

A recent controversy in California focused on the question of whether physicians opposed to same-sex relationships should be required to perform IVF for a lesbian couple. Guadalupe T. Benitez, a medical assistant from San Diego, sued doctors Christine Brody and Douglas Fenton of the North Coast Women's Care Medical Group after Brody told her that she had "religious-based objections to treating homosexuals to help them conceive children by artificial insemination," and Fenton refused to authorise a refill of her prescription for the fertility drug Clomid on the same grounds.[79][80] The California Medical Association had initially sided with Brody and Fenton, but the case, North Coast Women's Care Medical Group v. Superior Court, was decided unanimously by the California State Supreme Court in favor of Benitez on 19 August 2008.[81][82]

Nadya Suleman came to international attention after having twelve embryos implanted, eight of which survived, resulting in eight newborns being added to her existing six-child family. The Medical Board of California sought to have fertility doctor Michael Kamrava, who treated Suleman, stripped of his license. State officials allege that performing Suleman's procedure is evidence of unreasonable judgment, substandard care, and a lack of concern for the eight children she would conceive and the six she was already struggling to raise. On 1 June 2011 the Medical Board issued a ruling that Kamrava's medical license be revoked effective 1 July 2011.[83][84] [85]

Catholic objections

The Catholic Church opposes all kinds of in vitro fertilisation because, as with contraception, it separates the procreative purpose of the marriage act from its unitive purpose:

This particular doctrine, often expounded by the magisterium of the Church, is based on the inseparable connection, established by God, which man on his own initiative may not break, between the unitive significance and the procreative significance which are both inherent to the marriage act.

The reason is that the fundamental nature of the marriage act, while uniting husband and wife in the closest intimacy, also renders them capable of generating new life and this as a result of laws written into the actual nature of man and of woman. And if each of these essential qualities, the unitive and the procreative, is preserved, the use of marriage fully retains its sense of true mutual love and its ordination to the supreme responsibility of parenthood to which man is called. We believe that our contemporaries are particularly capable of seeing that this teaching is in harmony with human reason.[86]

According to the Catechism of the Catholic Church,

Techniques involving only the married couple (homologous artificial insemination and fertilization) are perhaps less reprehensible, yet remain morally unacceptable. They dissociate the sexual act from the procreative act. The act which brings the child into existence is no longer an act by which two persons give themselves to one another, but one that "entrusts the life and identity of the embryo into the power of doctors and biologists and establishes the domination of technology over the origin and destiny of the human person. Such a relationship of domination is in itself contrary to the dignity and equality that must be common to parents and children."[87]

The Catholic Church maintains that it is not objectively evil to be infertile, and advocates adoption as an option for such couples who still wish to have children:

The Gospel shows that physical sterility is not an absolute evil. Spouses who still suffer from infertility after exhausting legitimate medical procedures should unite themselves with the Lord's Cross, the source of all spiritual fecundity. They can give expression to their generosity by adopting abandoned children or performing demanding services for others.[87]

Gamete Intrafallopian Transfer (GIFT)[88] is not technically in vitro fertilisation because with GIFT, fertilisation takes place inside the body, not on a Petri dish. The Catholic Church nevertheless is concerned with it because "Some theologians consider this to be a replacement of the marital act, and therefore immoral."[89]

Availability and utilisation

In the USA, overall availability of IVF in 2005 was 2.5 IVF physicians per 100,000 population, and utilisation was 236 IVF cycles per 100,000.[90] Utilisation highly increases with availability and IVF insurance coverage, and to a significant extent also with percentage of single persons and median income.[90]

The cost of IVF rather reflects the costliness of the underlying healthcare system than the regulatory or funding environment,[91] and ranges, on average for a standard IVF cycle and in 2006 United States dollars, between $12,500 in the United States to $4,000 in Japan.[91] In Ireland, IVF costs around 4,000, with fertility drugs, if required, costing up to 3,000.[92] The cost per live birth is highest in the United States ($41,000[91]) and United Kingdom ($40,000[91]) and lowest in Scandinavia and Japan (both around $24,500[91]).

Many fertility clinics in the United States limit the upper age at which women are eligible for IVF to 50 or 55 years.[93] These cut-offs make it difficult for women older than fifty-five to utilise the procedure.[93]

In Australia, the average age of women undergoing ART treatment is 35.5 years among those using their own eggs (one in four being 40 or older) and 40.5 years among those using donated eggs.[94]

Legal status

Government agencies in China passed bans on the use of IVF in 2003 by unmarried women or by couples with certain infectious diseases.[95] Sunni Muslim nations generally allow IVF between married couples when conducted with their own respective sperm and eggs, but not with donor eggs from other couples. But Iran, which is Shi'a Muslim, has a more complex scheme. Iran bars sperm donation but allows donation of both fertilised and unfertilised eggs. Fertilised eggs are donated from married couples to other married couples, while unfertilised eggs are donated in the context of mut'ah or temporary marriage to the father.[96] The nation of Costa Rica has a complete ban on all IVF technology, it having been ruled unconstitutional by the nation's Supreme Court because it "violated life."[97] Costa Rica is the only country in the western hemisphere that forbids this technique. The Inter-American Court on Human Rights ruled out that the Costa Rican government has violated the human rights of infertile couples when it banned the use of this technique. According to the rule, Costa Rica had to enact legislation allowing the use of this type of procedure. The Court set a first dateline on February 2011 for a report on the question by the Costa Rican government. The latter missed the dateline and new datelines were set. All of them have been missed by the Costa Rican government. A law project sent reluctantly by the government of Pres. Laura Chinchilla was rejected at the Costa Rican parliament. Consequently, observers expect that Costa Rica will not abide to the request of the Inter-American Court on Human Rights. President Chinchilla, whose strong Catholic views have won her to be named officially as Preferred Daughter of the Virgin Mary has not publicly stated her position on the question of in vitro fertilisation. However, given the massive influence of the Catholic Church in her government any change in the status quo seems very unlikely La Costa Rica cat lica se atasca con la fertilizaci n in vitro CIDH Extends Deadline For Approval Of Law For In-Vitro Fertilization In Costa Rica. Federal regulations in the United States include screening requirements and restrictions on donations, but generally do not affect sexually intimate partners.[98] However, doctors may be required to provide treatments due to nondiscrimination laws, as for example in California.[82]

All major restrictions on single but infertile women using IVF were lifted in Australia in 2002 after a final appeal to the Australian High Court was rejected on procedural grounds in the Leesa Meldrum case. A Victorian federal court had ruled in 2000 that the existing ban on all single women and lesbians using IVF constituted sex discrimination.[99] Victoria's government announced changes to its IVF law in 2007 eliminating remaining restrictions on fertile single women and lesbians, leaving South Australia as the only state maintaining them.[100] The US state of Tennessee proposed a bill in 2009 that would have defined donor IVF as adoption.[101] During the same session another bill proposed barring adoption from any unmarried and cohabitating couple, and activist groups stated that passing the first bill would effectively stop unmarried people from using IVF.[102][103] Neither of these bills passed.[104][105]

IVF incidence

Israel has the highest world incidence of IVF, with 1657 procedures performed per million people per year. The second highest rate is in Iceland, with 899 procedures per million people per year. In the USA 126 procedures are performed per million people per year. Israel provides unlimited free in vitro procedures for its citizens for up to two children per woman under 45 years of age. In other countries the coverage of such procedures is limited if it exists at all. The Israeli Health Ministry says it spends roughly $3450 per procedure. In the USA an average cycle, from egg retrieval to embryo implantation, costs $12,400, and insurance companies that do cover treatment, even partially, usually cap the number of cycles they pay for.[106]

See also

References

Further reading

External links

ar: az:S ni mayaland rma bg: ca:Fecundaci in vitro cs:Oplodn n ve zkumavce de:In-vitro-Fertilisation et:Viljastamine katseklaasis es:Fecundaci n in vitro eu:In vitro ernalkuntza fa: fr:F condation in vitro ko: hi: hr:In vitro oplodnja it:FIVET he: - lt:Apvaisinimas in vitro ml: ms:Persenyawaan in vitro nl:In-vitrofertilisatie ja: no:In vitro-fertilisering pl:Zap odnienie pozaustrojowe pt:Fertiliza o in vitro ro:Fertilizare n vitro ru: simple:In vitro fertilisation sl:Oploditev z biomedicinsko pomo jo sh:In vitro oplodnja sr: fi:Koeputkihedelm itys sv:In vitro-fertilisering ta: th: uk: vi:Th tinh trong ng nghi m zh:






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