In vitro fertilisation

"Test tube baby" redirects here. For the TV programme, see Brainiac's Test Tube Baby.

In vitro fertilisation (IVF) is a technique in which egg cells are fertilised by sperm outside the woman's womb. IVF is a major treatment in infertility when other methods of achieving conception 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. The term in vitro, from the Latin, 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 containeners 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, which may be made of glass or plastic resins (contemporary test tubes may also be made of glass or plastic resin).

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Oocyte with surrounding granulosa cells

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"Naked" Oocyte

History

Based on the findings of Min Chueh Chang's application of in vitro fertilisation on animals, the technique was specifically developed for humans in the United Kingdom by Doctors Patrick Steptoe, John Webster and Robert Edwards. The first so-called "test-tube baby", Louise Brown, was born in Oldham, England, as a result on July 25, 1978 amid intense controversy over the safety and morality of the procedure.

Subhash Mukhopadhyay became the first physician in India, and the second in the world after Steptoe and Edwards, to perform the first in vitro fertilisation resulting in a test tube baby "Durga" (alias Kanupriya Agarwal) on October 3 1978. Facing social ostracism, bureaucratic negligence, reprimand and insult instead of recognition from the Marxist West Bengal government and refusal of the Government of India to allow him to attend international conferences, he committed suicide in his Calcutta residence in 1981.

Major pioneering developments in IVF also occurred in Australia under the leadership of Carl Wood, Alan Trounson and Ian Johnston. The world's third IVF baby, Candice Reed was born on June 23, 1980 in Melbourne, Australia.

The first successful IVF treatment in the USA (producing Elizabeth Jordan Carr) took place in 1981 under the direction of Doctors Howard Jones and Georgeanna Seegar Jones in Norfolk, Virginia. Since then IVF has exploded in popularity, with as many as 1% of all births now being conceived in-vitro, with over 115,000 born in the USA to date. At present, the percentage of children born after IVF or intracytoplasmic sperm injection (ICSI) has been up to 4% of all babies born in Denmark.

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.

Thus, 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 already gone through pregnancy. The donated oocyte can be fertilised in a crucible. If the fertilisation is successful, the fertilised egg 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 oestradiol level and, by means of gynaecologic ultrasonography, follicular growth. Typically approximately 10 days of injections will be necessary. Endogenous ovulation is blocked by the use of GnRH agonists or GnRH antagonists.

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 anaesthesia.

Oocyte is injected during ICSI

IVF laboratory

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. 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

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 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. Blastocysts may give higher pregnancy rates if embryo quality is in doubt. However, many studies have shown no difference in pregnancy rates between day-3 and day-5 transfers. In Europe, day-2 transfers 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 and New Zealand, a maximum of two embryos are transferred except in unusual circumstances. 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. Often, several embryos are passed into the uterus to improve chances of implantation and pregnancy.

Blastocyst for transfer

Post-transfer

The patient has to wait two weeks before she returns to the clinic for the pregnancy test. During this time she may receive progesterone—a hormone that keeps the uterus lining thickened and suitable for implantation. Many IVF programmes provide additional medications as part of their protocol.

Acupuncture

According to the latest reports published in Fertility and Sterility, if done correctly, Acupuncture significantly improves IVF success rate. Acupuncture is integrated into the treatment protocols by many progressive fertility clinics in the United States. A study of hypnotherapy also suggests a higher success rate when integrated with treatment [2].

Chance of a successful pregnancy is approximately 20-30% for each IVF cycle, although selected clinics are now able to quote rates up to 50% per cycle. [3] There are many factors that determine success rates including the age of the patient, 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.

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.

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

Complications

The major complication of IVF is the risk of multiple births.[4] 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 does occur, but is rare (<1%) and would lead to identical twins. 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. Major birth defect include chromosomal abnormalities, genetic imprinting defects, and multiple organ abnormalities. Hansen et al conducted a systematic review of published studies (including ICSI) and found a 30-40% increase risk of birth defects associated with assisted reproductive technology when compared to children born after spontaneous conception. Possible explanations offered were the underlying cause of the infertility, factors associated with IVF/ICSI, culture conditions, and medications, however, the actual cause is not known.

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 (See http://www.motherjones.com/news/feature/2006/07/souls_on_ice.html) 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.

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.

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.

Developments

Intracytoplasmic sperm injection (ICSI) is a more recent development associated with IVF which allows the sperm to be directly injected in to the egg using micromanipulation. This is used for sperm that have difficulty penetrating the egg and when sperm numbers are very low. ICSI results in success rates equal to IVF fertilisation.

Preimplantation genetic diagnosis (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).

Jane Mohr, 38, of Manhattan Beach Calif., gave birth to the nation's first set of triplets born 21 months apart due to in vitro fertilisation (IVF) and long-term embryo storage. Jane gave birth November 29, 1988 to two daughters, Mollie McKenna and Hannah Christina Mohr, nearly two years after the birth of her son, Cooper Patrick Mohr.

Ethics

Issues

Certain ethical issues have been raised from the beginning when IVF was introduced. These concerns include:

• The bypassing the natural method of conception.
• The creation of life in the laboratory.
• Fertilisation more embryos than will be needed.
• Discarding of excess embryos.
• Unnatural environment for embryos.
• Use of untested technology.
• Not affordable for many.
• Misallocation of medical resources.
• Creation of embryos, then freezing them, and keeping them "in limbo".
• Exposition of embryos to unnatural substances.
• Destruction of embryos in research.
• Potential to create embryos for medical purposes.
• Potential to select embryos (PGD).
• Potential to modify embryos.
• Facilitation of the idea that embryos are commodities.
• Financial rewards for IVF doctors dissuade them from recommending other methods to couples.
• Infertility is treated as a disease and not as a symptom of underlying medical problems.

Separating the traditional mother-father model

The IVF process requires sperm, eggs, and a uterus. To achieve a pregnancy any of these requirements can be provided by a third party (or more parties): third party reproduction. This has created additional ethical and legal concerns. The use of IVF provides also greater range of options for single people and same-sex couples wishing to have children. Although both groups already raise children, IVF facilitates this process. Some people object that this could give psychological problems to the child if they grow up without a mother/father role-model.

A number of cases have achieved notoriety:

• In 2001, a French woman received worldwide publicity when she posed as the wife of her brother in order to give birth to a donor egg fertilised by his sperm. Some saw this as a form of incest; others thought it would prove psychologically unhealthy for the child when he learned how he was delivered; whereas other people simply couldn't see anything wrong with the situation.
• 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.

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 a biological 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.

Religious objections

The Roman Catholic Church is opposed to in vitro fertilisation in all instances and advocates that infertility is a call from God to adopt children. 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." Also, embryos are discarded in the process causing them, according to the Church, to die. Some estimates of the numbers of embryos involved reach 6 million. Catholics and those of other faiths see embryos as human lives with the same rights as all others and, therefore, view this procedure as always unacceptable. However, the Church allows the use of more natural techniques such as Natural Family Planning, which seek to naturally treat the underlying causes of infertility.

Regulatory events

While in the United States IVF programmes operate under voluntary guidelines, programmes in many other countries are subject to regulations that regulate many aspects of IVF practice. In such settings regulations may dictate:

• The number of oocytes that can be fertilised.
• The number of embryos that can be transferred.
• The use of cryopreservation.
• The use of third party reproduction.
• The ability to perform tests or interventions on the embryo.

In 2004, the government of Italy made it a crime to freeze human embryos or to perform preimplantation diagnosis.

External links

• Find a Clinic offering IVF in the UK
• Human Fertilisation and Embryology Authority
• CDC Report on IVF Clinics
• Introduction to IVF and Infertility
• Test Tube Babies on PBS
• In Vitro Fertilisation FAQs at WikiFAQ
• Ethical debate: In vitro fertilisation (BMJ)
• Late honour for test tube pioneer
• It's official: Kanupriya's India’s first test-tube girl
• Common Concerns About IVF