artificial-insemination

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artificial insemination

Introduction of semen into a female's vagina or cervix by means other than sexual intercourse. First developed for animal breeding in the early 20th century in Russia, it is now also used to induce pregnancy in women whose partners cannot impregnate them. The partner's (or other donor's) semen is inserted with a syringe. Though reasonably successful, artificial insemination in humans raises moral issues that are not yet fully resolved. In livestock, deep-frozen semen from a male animal can be stored for long periods without losing its fertility, thus allowing a single bull to sire as many as 10,000 calves a year.

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Encyclopedia Britannica, 2008. Encyclopedia Britannica Online.

Artificial insemination

AIH redirects here. For the indie rock band abbreviated AIH, see Architecture in Helsinki

Artificial insemination (AI) is the process by which sperm is placed into the reproductive tract of a female for the purpose of impregnating the female by using means other than sexual intercourse.

Specifically, in artificial insemination, freshly ejaculated sperm, or sperm which has been frozen and thawed, is placed in the cervix (intracervical insemination) (ICI)) or in the female's uterus (intrauterine insemination) (IUI) by artificial means.

Modern techniques for human artificial insemination were first developed for the dairy cattle industry to allow many cows to be impregnated with the sperm of a bull with traits for improved milk production.

Human artificial insemination

In humans artificial inseminations is used as assisted reproductive technology primarily to treat infertility but is increasingly used to enable women without a male partner (i.e. single women and lesbians) to become pregnant and to produce children by using sperm provided by a sperm donor. The woman is the genetic and gestational mother of the child, and the sperm donor is the genetic or biological father of the child.

Preparations

A sperm sample will be provided by the male partner of the woman undergoing artificial insemination, but sperm provided through sperm donation by a sperm donor may be used if, for example, the woman's partner produces too few motile sperm, if he carries a genetic disorder, or if the woman has no male partner. Sperm is usually obtained through masturbation or the use of an electrical stimulator, although a special condom, known as a collection condom, may be used to collect the semen during intercourse.

The man providing the sperm is usually advised not to ejaculate for two to three days before providing the sample in order to increase the sperm count.

A woman's menstrual cycle is closely observed, by tracking basal body temperature (BBT) and changes in vaginal mucous, or using ovulation kits, ultrasounds or blood tests.

When using intrauterine insemination (IUI), the sperm must immediately be “washed” in a laboratory and concentrated in Hams F10 media without L-glutamine, warmed to 37C. (Adams, Robert, M.D."invitro fertilization technique", Monterey, CA, 1988). The process of “washing” the sperm increases the chances of fertilization and removes any mucus and non-motile sperm in the semen.Pre and post concentration of motile sperm is counted.

If sperm is provided by a sperm donor through a sperm bank, it will be frozen and quarantined for a particular period and the donor will be tested before and after production of the sample to ensure that he does not carry a transmissible disease. Sperm samples donated in this way are produced through masturbation by the sperm donor at the sperm bank. A chemical known as a cryoprotectant is added to the sperm to aid the freezing and thawing process. Further chemicals may be added which separate the most active sperm in the sample as well as extending or diluting the sample so that vials for a number of inseminations are produced.

Procedure

When an ovum is released, fertile semen provided by the woman's male partner, or by a sperm donor who is a fertile male who is unrelated to, and may be unknown by, the woman, is inserted into the woman's vagina or uterus. The semen may be fresh or it may be frozen semen which has been thawed. Where donor sperm is supplied by a sperm bank, it will always be frozen and will need to be thawed before use. In the case of vaginal artificial insemination, semen is inserted into the vagina by means of a needleless syringe. A longer tube, known as a 'tom cat' may be attached to the end of the syringe to faciliate deposit of the semen deeper into the vagina. The woman is genrally advised to lie still for half and hour or so after the insemination to allow fertilization to take place. Alternatively, semen may be placed in the vagina by means of a specially designed cervical cap which holds the semen in place for a period of time, usually for several hours. Using this method, a woman may go about her usual activities while the cervical cap holds the semen in place in the vagina. Where semen is inserted into the woman's uterus, only 'washed' semen may be used and this is inserted by means of a catheta. Specially designed equipment is also available for carrying out artificial inseminations. Semen is occasionally inserted twice within a 'treatment cycle'. If the procedure is successful, the woman will conceive and carry to term a baby. A pregnancy resulting from artificial insemination is no different from any other pregnancy but there is a slight increased likelihood of multiples rather than a singleton baby if drugs are used for a 'stimulated' cycle.

Variations

Artificial insemination has several variations both regarding the donor of the sperm and the techniques used.

Donor variations

Either sperm provided by the woman's husband or partner (artificial insemination by husband, AIH) or sperm (known as "donor sperm") provided by a known or anonymous sperm donor (artificial insemination by donor, AID or DI) can be used.

Earlier, a popular form of artificial insemination was AIC, in which the sperm of the husband and a donor were mixed. The advantage of this stated that the husband was not the biological father of the child. This was important in an age where artificial insemination was considered to be immoral and tantamount to adultery, with the resulting child being considered as illegitimate and having no inheritance rights. The popularity of AIC has reduced to almost nil for a number of reasons, including advances in genetic testing which make it fairly easy to identify the genetic father with a blood test, the advance of medical treatments for male infertility (such as ICSI), and the declining stigma of assisted reproductive technologies in general.

Techniques

The easiest way to inseminate is by intracervical insemination (ICI), where semen is injected high into the cervix with a needle-less syringe. This process most closely replicates the way in which semen is deposited by the penis in the cervix or fornix when the male ejaculates during vaginal intercourse. However, more technical procedures may be used which increase the chances of conception. For example, 'washed sperm', that is, spermatozoa which have been removed from most other components of the seminal fluids, can be injected directly into a woman's uterus in a process called intrauterine insemination (IUI). If the semen is not washed it may elicit uterine cramping, expelling the semen and causing pain, due to content of prostaglandins. (Prostaglandins are also the compounds responsible for causing the myometrium to contract and expel the menses from the uterus, during menstruation.)

IUI can furthermore be combined with intratubal insemination (ITI), into the Fallopian tube although this procedure is no longer generally regarded as having any beneficial effect compared with IUI ITI however, should not be confused with gamete intrafallopian transfer, where both eggs and sperm are mixed outside the woman's body and then immediately inserted into the Fallopian tube where fertilization takes place. See also in vitro fertilisation (IVF) techniques which may involve the use of partner or donor sperm.

Success rates

Success rates for artificial insemination may be very misleading, since many factors including the age and health of the recipient have to be included to give a meaningful answer, e.g. definition of success and calculation of the total population. For couples whose infertility is unexplained, unstimulated IUI is no more effective than natural means of conception.

Generally, it is 10 to 15% per cycle using ICI, and and 15-20% per cycle for IUI.

Controversy

Artificial insemination has become a significant issue in recent years, particularly in debates revolving around same sex parenting, single mother parenting and surrogate parenting. Legal issues have arisen in cases where the gestational (and possibly genetic) mother decides to keep the child. Likewise, there have been debates over the rights and obligations of sperm donors.

Artificial insemination in livestock and pets

Artificial insemination is used in animals to propagate desirable characteristics of one male to many females or overcome breeding problems, particularly in the cases of horses, cattle, pigs, pedigree dogs, and honeybees. Semen is collected, extended, then cooled or frozen. It can be used on site or shipped to the female's location. The small plastic tube holding the frozen semen is referred to as a "straw". To allow the sperm to remain viable during the time before and after it is frozen, the semen is mixed with a solution containing glycerol or other cryoprotectants. An "extender" is a solution that allows the semen from a donor to impregnate more females by making insemination possible with fewer sperm. Antibiotics, such as streptomycin, are sometimes added to the sperm to control some venereal diseases.

Artificial insemination of farm animals is very common in today's agriculture industry in the developed world, especially for breeding dairy cattle (75% of all inseminations) and swine (up to 85% of all inseminations). It provides an economical means for a livestock grower to breed their herds with males having very desirable traits.

Although common with cattle and swine, AI is seldom practised in the breeding of horses. Most equine associations and race tracks in North America only accept horses that have been conceived under "natural cover", or actual physical mating between a mare and a stallion. All Thoroughbred bloodstock (race horses), are conceived naturally, no AI is allowed in Thoroughbred breeding.