In vitro fertilisation

In vitro fertilisation (IVF) is a process by which egg cells are fertilised by sperm outside of the 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.

Oocyte with surrounding granulosa cells

"Naked" Egg

Main article: 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. This is used when parents are having infertility problems or they want to have multiple births

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.

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. Due to the costs of the procedure, IVF is generally attempted only once 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 zygote will be transferred into the uterus, within which 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 luteinising hormone (LH).

Egg retrieval

Main article: Transvaginal oocyte retrieval

When follicular maturation is judged to be adequate, human chorionic gonadotropin (β-hCG) is given. This agent, which acts as an analogue of luteinising 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.

Oocyte is injected during ICSI

Fertilization

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.

8-cell embryo for transfer

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, 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.^[1]. In Europe, transfers after 2 days are common.

Embryo transfer

Main article: 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. 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. 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.

Blastocyst for transfer

Success rates

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 i** is the risk of multiple births.[2] 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 ^[2]. 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.^[3]

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 Hospital, located in Tokyo, to use in vitro fertilisation for HIV couples, the Health, Labour 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. ^[4]

Cryopreservation

Main article: Cryopreservation

Embryo cryopreservation

The first pregnancy derived from a frozen human embryo was reported by Allan Trounson & Linda Mohr in 1983 (although the pregnancy aborted spontaneously at about 20 weeks of gestation); the first term pregnancies derived from frozen human embryos were reported by Zeilmaker et al. and the first human baby hatched via a rate frozen freezing process was born in 1984. Since then and up to 2008 it is estimated that between 350,000 and half a million IVF babies have been born from embryos controlled rate frozen and then stored in liquid nitrogen; additionally a few hundred births have been born from vitrified oocytes but firm figures are hard to come by.

On the safety of embryo cryopreservation, a 2008 study reported at the European Society for Human Reproduction and Embryology discovered that children born from frozen embryos did “better and had a higher birth weight” than children born from a fresh transfer. The study was conducted out of Copenhagen and evaluated babies born during the years 1995–2006. 1267 children born after Frozen Embryo Replacement (FER), via controlled-rate freezers and storage in liquid nitrogen, were studied and categorised into three groups. 878 of them were born using frozen embryos that were created using standard in vitro fertilisation in which the sperm were placed into a dish close to the egg but had to penetrate the egg on their own. 310 children were born with frozen embryos created using ICSI in which a single sperm was injected into a single egg, and 79 were born where the method of creation of the embryos was not known. 17,857 babies born after a normal IVF/ICSI with fresh embryos were also studied and used as a control group or reference group. Data on all of the children’s outcomes were taken regarding birth defects, birth weights, and length of pregnancy. The results of the study showed that the children who came from frozen embryos had higher birth weights, gave longer pregnancies and produced fewer “pre-term” births. There was no difference in the rate of birth defects whether the children came from frozen embryos or fresh embryos. In the FER group, the birth defect rate was 7.7% compared to the fresh transfer group which was slightly higher at 8.8%. The scientists also found that the risk for multiple pregnancies was increased in the fresh embryo transfers. Around 11.7% of the ICSI and 14.2% of the IVF frozen cases were multiple pregnancies. In the case of fresh embryos, 24.8% of the ICSI and 27.3% of the IVF were multiple pregnancies. It should also be noted that maternal age was significantly higher in the FER group. This is significant since based on age one would have expected a higher rate of problems and birth defects. The study adds to the body of knowledge suggesting that traditional embryo freezing is a safe procedure. It was unclear however why the frozen embryo children did better than their fresh embryo counterparts

If multiple embryos are generated, patients may choose to freeze embryos that are not transferred. Those embryos are slow frozen and then placed in liquid nitrogen and can be preserved for a long time. There are currently 500,000 frozen embryos in the United States.[3] 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.^[5] It should be note that the rate of thaw leading to successful pregnancies is still very low.

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.

Variations

There are several variations or improvements of IVF:

PGD

Main article: Preimplantation genetic diagnosis

PGD (Preimplantation Genetic Diagnosis) can be performed on embryos prior to the embryo transfer. A similar, but more general test has been developed called Preimplantation Genetic Haplotyping (PGH).

ICSI

ICSI (Intracytoplasmic Sperm Injection) is a more recent development associated with IVF which allows the sperm to be directly injected in to the egg. 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

In the process of ZIFT (Zygote Intrafallopian Transfer), eggs are removed from the woman, fertilised and then placed in the woman's fallopian tubes rather than the uterus.

GIFT

In the process of GIFT (Gamete Intra-Fallopian 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, and not an in vitro fertilisation.

Acupuncture

An increasing number of fertility specialists and centers offer acupuncture as a part of their IVF protocol. Limited, but supportive, evidence from clinical trials and case series suggests that acupuncture may improve the success rate of IVF and the quality of life of patients undergoing IVF and that it is a safe adjunct therapy^[6]. A systematic review and meta-analysis published in the British Medical Journal found that complementing the embryo transfer process with acupuncture was associated with significant and clinically relevant improvements in clinical pregnancy (where the expected number of patients needed to be treated to produce 1 additional pregnancy was 10), ongoing pregnancy (NNT 9), and live birth (NNT 9)^[7].

Jon and Kate Plus Eight

According to the official web site for the television program Jon and Kate Plus Eight, they used the reproductive technique intrauterine insemination (IUI) to become pregnant. They did not use in vitro fertilization (IVF).^[8]

Acupuncture Mechanisms

Four mechanisms by which it has been suggestsed that acupuncture may improve IVF outcomes are^[6]:

• Neuroendocrinological modulations
• Increased blood flow to uterus and ovaries
• Modulation in cytokines
• Reducing stress, anxiety and depression

Electro-acupuncture in oocyte retrieval for IVF

Electro-acupuncture has been found to be less successful than conventional medical analgesia at reducing pain during oocyte retrieval for IVF, although it results in shorter hospitalisation times and lower costs^[9].

History

The first pregnancy achieved following in vitro 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 on 25th July 1978, followed by Alastair MacDonald on 14th January 1979, the world’s first and second 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

See also: Beginning of pregnancy controversy

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.

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.^[10]

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 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 to carry out its function.^[11]

Gays and Lesbians

A recent controversy in California focused 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 authorise a refill of her prescription for the fertility drug Clomid on the same grounds.^[12][13] The case, North Coast Women's Care Medical Group v. Superior Court was decided in favor of Benitez on August 19, 2008.^[14].

Religious objections

The Roman 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 [of "observing the natural law"], 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.^[15]

According to the Catechism of the Catholic Church,

Techniques involving only the married couple (homologous artificial insemination and fertilization) [...] 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."^[16]

The Catholic Church advocates that infertility is a call from God to adopt children because

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.^[16]

Also, embryos are sometimes discarded in the in vitro fertilisation process, resulting in their death. 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 the loss of innocent lives.

Although some mistakenly consider Gamete Intrafallopian Transfer (GIFT) to be in vitro fertilisation, it is not. With GIFT, fertilisation takes place inside the body and not on a Petri dish. The Catholic Church, nevertheless, does not condone it because "Some theologians consider this to be a replacement of the marital act, and therefore immoral."^[17]

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.

See also

• Assisted reproduction
• Commercial surrogacy
• Reproduction
• Surrogacy
• Carl Wood

References

Further reading

• Hope T, Lockwood G, Lockwood M (June 1995). "An Ethical Debate: Should older women be offered in vitro fertilization? The interests of the potential child". BMI 310 (6992): 1455–6. PMID 7613283. http://www.bmj.com/cgi/content/full/310/6992/1455. 

• Seng SW, Yeong CT, Loh SF, Sadhana N, Loh SK (March 2005). "In-vitro fertilisation in women aged 40 years and above". Singapore Med J 46 (3): 132–6. PMID 15735878. http://www.sma.org.sg/smj/4603/4603a4.pdf. 

External links

• Guide to infertility
• CDC Report on IVF Clinics
• Test Tube Babies on PBS
• BBC profile of Louise Brown (July, 2003)
• Well maintained blog on all current matters of IVF --79.195.245.210 (talk) 13:34, 26 November 2008 (UTC)