In vitro fertilisation

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In vitro fertilisation or fertilization^[1] (IVF) is a process by which egg cells are fertilised by sperm outside the woman's womb, in vitro. IVF is a major treatment in infertility when other methods of assisted reproductive technology have failed. The process involves hormonally controlling the ovulatory process, removing ova (eggs) from the woman's ovaries and letting sperm fertilise them in a fluid medium. The fertilised egg (zygote) is then transferred to the patient's uterus with the intent to establish a successful pregnancy.

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Oocyte with surrounding granulosa cells

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"Naked" Egg

"In vitro"

The term in vitro, from the Latin root 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. (Petri-dishes may also be made of plastic resins.) However, the IVF method of Autologous Endometrial Coculture is actually performed on organic material, but is yet called in vitro.

Indications

Initially IVF was developed to overcome infertility due to problems of the fallopian tube, but it turned out that it was successful in many other infertility situations as well. The introduction of intracytoplasmic sperm injection (ICSI) addresses the problem of male infertility to a large extent.

Thurr, for IVF to be successful it may be easier to say that it requires healthy ova, sperm that can fertilise, and a uterus that can maintain a pregnancy. Cost considerations generally place IVF as a treatment when other less expensive options have failed.

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 fertilised egg will be transferred into the uterus, within whitch it will develop into an embryo.

Method

Ovarian stimulation

Treatment cycles are typically started on the third day of menstruation and consist 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. Spontanenous ovulation during the cycle is prevented by the use of GnRH agonists or GnRH antagonists, which block the natural surge of luteinizing hormone (LH).

Egg retrieval

When follicular maturation is judged to be adequate, human chorionic gonadotropin (β-hCG) is given. This agent, which acts as an analogue of luteinizing hormone, would cause ovulation about 36 hours after injection, but a retrieval procedure takes place just prior to that, in order to recover the egg cells from the ovary. The eggs are retrieved from the patient using a transvaginal technique 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. The retrieval procedure takes about 20 minutes and is usually done under conscious sedation or general anesthesia.

Fertilisation

In the laboratory, the identified eggs are stripped of surrounding cells and prepared for fertilisation. In the meantime, semen is prepared for fertilisation by removing inactive cells and seminal fluid. 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. The sperm and the egg are incubated together (at a ratio of about 75,000:1) in the culture media for about 18 hours. By that time fertilisation should have taken place and the fertilised egg would show two pronuclei. In situations where the sperm count is low, a single sperm is 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 has reached the 6-8 cell stage.

Selection

Laboratories have developed grading methods to judge oocyte and embryo quality. Typically, embryos that have reached the 6-8 cell stage are transferred three days after retrieval. In many American and Australian programmes^{[citation needed]}, however, embryos are placed into an extended culture system with a transfer done at the blastocyst stage, especially if many good-quality day-3 embryos are available. Blastocyst stage transfers have been shown to result in higher pregnancy rates.^[2]. In Europe, day-2 transfers are common. ^{[citation needed]}

Embryo transfer

Embryos are graded by the embryologist based on the number 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 the UK, Australia and New Zealand, a maximum of two embryos are transferred except in unusual circumstances. For instance, a woman over 35 may have up to three embryos transferred. This is to limit the number of multiple pregnancies. 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

While the overall live birth rate via IVF in the U.S. is about 27% per cycle (33% pregnancy rate), the chances of a successful pregnancy via IVF vary widely based on the age of the woman (or, more precisely, on the age of the eggs involved). [2] Where the woman's own eggs are used as opposed to those of a donor, for women under 35, the pregnancy rate is commonly approximately 43% per cycle (36.5% live birth), while for women over 40, the rate falls drastically - to only 4% for women over 42. [3] Other factors that determine success rates include the quality of the eggs and sperm, the duration of the infertility, the health of the uterus, and the medical expertise. It is a common practice for IVF programmes to boost the pregnancy rate by placing multiple embryos during embryo transfer. A flip side of this practice is a higher risk of multiple pregnancy, itself associated with obstetric complications. Another counterintuitive finding is that the risk of twins and higher order multiple births increase in patients undergoing IVF, even when only one embryo is transferred ^[3].

A recent technique is to bathe an embryo in a culture of nutrients for five days until it reaches a developmental landmark known as the blastocyst stage. The doctors then determine which embryos are most likely to thrive long term. The best quality of these are transferred into a woman's uterus. In this way it is possible to enable pregnancy without the risk of multiple pregnancy. This technique is relatively new and has yet to be well tested.

IVF programmes generally publish their pregnancy rates. However, comparisons between clinics are difficult as many variables determine outcome. Furthermore, these statistics depend strongly on the type of patients selected. An IVF success test has been invented for women and couples trying to conceive to predict individualised chances of success from epidemiological data [4].

There are many reasons why pregnancy may not occur following IVF and embryo transfer, including

The timing of ovulation may be misjudged, or ovulation may not be able to be predicted or may not occur
Attempts to obtain eggs that develop during the monitored cycle may be unsuccessful
The eggs obtained may be abnormal or may have been damaged during the retrieval process
A semen specimen may not be able to be provided
Fertilisation of eggs to form embryos may not occur
Cleavage or cell division of the fertilised eggs may not take place
The embryo may not develop normally
Implantation may not occur
Equipment failure, infection and/or human error or other unforeseen and uncontrollable factors, which may result in the loss of or damage to the eggs, the semen sample and/or the embryos^[4]

According to a 2005 Swedish study published in the Oxford Journal 'Human Reproduction' 166 women were monitored starting one month before their IVF cycles and the results showed no significant correlation between psychological stress and their IVF outcomes. 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.

Complications

The major complication of IVF is the risk of multiple births.[5] 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., England) 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 < 2500 g ^[5]. However recent evidence suggest that singleton offspring after IVF is at higher risk for lower birth weight for unknown reasons.

Another risk of ovarian stimulation is the development of ovarian hyperstimulation syndrome.

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.

Birth defects

The issue of birth defects remains a controversial topic in IVF. A majority of studies do not show a significant increase after use of IVF. Some studies suggest higher rates for ICSI , while others do not support this finding.^[6]

Japan's government prohibited the use of in vitro fertilization procedures for couples, inwhich both partners are infected with HIV virus. Despite the fact that the ethics committees previously allowed the Ogikubo Hospital, located in Tokyo, to use in vitro fertilization for HIV couples, the Health, Labor and Welfare Ministry 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 the AIDS virus from sperm. ^[7]

Cryopreservation

Embryo cryopreservation

If multiple embryos are generated, patients may choose to freeze embryos that are not transferred. Those embryos are placed in liquid nitrogen and can be preserved for a long time. There are currently 500,000 frozen embryos in the United States.[6] 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 embryos resulting from fertility treatments may be donated to another woman or couple, and embryos may be created, frozen and stored specifically for transfer and donation by using donor eggs and sperm.

Oocyte cryopreservation

Cryopreservation of unfertilised mature oocytes has been successfully accomplished, e.g. in women who are likely to lose their ovarian reserve due to undergoing chemotherapy.^[8]

Ovarian tissue cryopreservation

Cryopreservation of ovarian tissue is of interest to women who want to preserve their reproductive function beyond the natural limit, or whose reproductive potential is threatened by cancer therapy. Research on this issue is promising.

Adjunctive interventions

There are several variations or improvements of IVF, such as ICSI, ZIFT, GIFT and PGD.

ICSI

(ICSI) is a more recent development associated with IVF which allows the sperm to be directly injected in to the egg using. This is used where 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 IVF fertilisation.

===ZIFT=== eggs are removed from the woman, fertilised and then placed in the woman's fallopian tubes rather than the uterus.

GIFT

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, and not an in vitro fertilisation.

PGD

PGD can be performed on embryos prior to the embryo transfer. A similar, but more general test has been developed called Preimplantation Genetic Haplotyping (PGH). But success rate of PGD is very less.

History

The first pregnancy achieved following invitro human fertilisation of a human oocyte was reported in The Lancet from the Monash team in 1973, although it only lasted a few days and would today be called a biochemical pregnancy. This was followed by a tubal ectopic pregnancy from Steptoe and Edwards in 1976, resulting from the successful partnership with Bob Edwards which resulted in the birth of Louise Brown in 1978, Courtney Cross, also in 1978, and another unnamed birth from Oldham, the world’s first IVF babies. This was followed by the birth of Candice Reed in Melbourne in 1980. 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 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 requirement 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 user-friendly both for staff and patients.

The ability to freeze and subsequently thaw and transfer embryos has also significantly improved the effectiveness of IVF. The other very significant milestone in IVF was the development of the intra cytoplasmic sperm injection of single sperms by Andre van Steirtegham in Brussels,1992. This has enabled men with minimal sperm production to achieve pregnancies, sometimes in conjunction with sperm recovery, using a testicular fine needle or open testicular biopsy, with some men even with kleinfelter’s syndrome occasionally achieving pregnancy. Thus, IVF has become the final solution for most fertility problems, moving from tubal disease to male factor, idiopathic subfertility, endometriosis, advancing maternal age, and anovulation not responding to ovulation induction.

Ethics

Issues

The IVF process requires sperm, eggs and a uterus. To achieve a pregnancy any of these requirements can be provided by a third person: third party reproduction. This has created additional ethical and legal concerns.^{[citation needed]}

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.^[9]

Pregnancy past menopause

While menopause has set a natural barrier to further conception, IVF has allowed women to be pregnant in their fifties and sixties. Women whose uteruses have 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 to carry out its function.^[10]

Gays and Lesbians

A recent controversy in California focussed on the question of whether physicians opposed to homosexuality 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 authorize a refill of her prescription for the fertility drug Clomid on the same grounds.^[11]^[12] The case, North Coast Women's Care Medical Group v. Superior Court was decided in favor of Benitez on August 19, 2008.^[13]

Religious objections

The Roman Catholic Church is opposed to most kinds of in vitro fertilisation (although GIFT is accepted at certain conditions because fertilisation takes place inside the body and not inside a Petri dish [7]) and advocates that infertility is a call from God to adopt children. According to the Catholic Church, it "infringe[s] the child's right to be born of a father and mother known to him and bound to each other by marriage."^[14] Also, embryos are sometimes discarded in the process, resulting in their demise. Catholics and many people of other faiths see embryos as human lives with the same rights as all others and, therefore, view the destruction of embryos as unacceptable.

Coping with IVF

Due to the emotional and financial aspects of infertility treatment, many feel isolated and sometimes become depressed. Online support forums and message boards have become a popular way for sufferers to exchange both information and support. Popular forums include International Agency for Prevention of Infertility (IAPI) Fertility Friends, IVFConnections, IVF.ca, Ivf-Infertility.com, INCIID, and IVF World.

References

International Agency for Prevention of Infertility (IAPI)

Most updated Information on prevention of infertility

^ See American and British English spelling differences.
^ Papanikolaou EG, Camus M, Kolibianakis EM, Van Landuyt L, Van Steirteghem A, Devroey P (2006). "In Vitro Fertilization with Single Blastocyst-Stage versus Single Cleavage-Stage Embryos". N Engl J Med. 354: 1139. doi:10.1056/NEJMoa053524. PMID 16540614.{{cite journal}}: CS1 maint: multiple names: authors list (link)
^ Blickstein I, Jones C, Keith LG. Zygotic splitting rates following single embryo transfers in in-vitro fertilization. N Engl J Med 2003;348:2366-2367
^ Abington Reproductive Medicine, In Vitro Fertilization (IVF): Why Pregnancy May Not Occur. (2006)
^ Olivennes F, Mannaerts B, Struijs M, Bonduelle M, Devroey P (2001). "Perinatal outcome of pregnancy after GnRH antagonist (ganirelix) treatment during ovarian stimulation for conventional IVF or ICSI: a preliminary report". Hum. Reprod. 16 (8): 1588–91. doi:10.1093/humrep/16.8.1588. PMID 11473947.{{cite journal}}: CS1 maint: multiple names: authors list (link)
^ Kurinczuk JJ (2003). "Safety issues in assisted reproduction technology. From theory to reality--just what are the data telling us about ICSI offspring health and future fertility and should we be concerned?". Hum Reprod. 18 (5): 925–31. doi:10.1093/humrep/deg217. PMID 12721163.
^ Japan Bans in Vitro Fertilization for HIV Couples
^ Porcu E, Fabbri R, Damiano G, Fratto R, Giunchi S, Venturoli S (2004). "Oocyte cryopreservation in oncological patients". Eur J Obstet Gynecol Reprod Biol. 113 Suppl 1: S14–6. doi:10.1016/j.ejogrb.2003.11.004. PMID 15041124.{{cite journal}}: CS1 maint: multiple names: authors list (link)
^ Ayers C (2004). "Mother wins $1m for IVF mix-up but may lose son". Timesonline. [1].
^ Parks, Jennifer A. (1996). "A closer look at reproductive technology and postmenopausal motherhood". CMAJ. 154 (8): 1189–91. PMID 8612255.
^ JM Appel. May Doctors Refuse Infertility Treatments to Gay Patients? The Hastings Center Report, 2006;36(4):20-21.
^ M. Dolan. State high court may give gays another victory. Los Angeles Times May 29, 2008.
^ M. Dolan. California doctors can't refuse treatment to gays on religious grounds, court rules. Los Angeles Times. August 19, 2008.
^ Catechism of the Catholic Church section 2376

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