ART covers a wide spectrum of technologies. For people having problems conceiving, it is common to begin treatment using techniques that include stimulating the ovaries, artificial insemination, or artificial insemination using donor sperm.
Stimulating the Ovaries (ovulation induction)
Ovulation induction is a process that encourages a woman’s ovaries to release eggs, in order to maximise her chance of becoming pregnant through sexual intercourse or artificial insemination. It is used for women who are producing low levels of hormones for ovulation (and therefore ovulating infrequently), or who are not ovulating at all. It involves taking medication in the form of tablets or injections, to stimulate a woman’s hormones.
Artificial insemination (AI)
Artificial insemination is also known as intrauterine insemination (IUI). It involves inserting the sperm of a male partner (or donor) through the neck of a woman’s womb (her cervix) and into her uterus, close to the time that the woman ovulates (releases eggs). It is used when for example, a male partner has mechanical difficulties with intercourse (such as inability to achieve erection or structural problems with the penis); when a man has frozen sperm (eg. before cancer treatment); or when a woman does not have a partner (see donor insemination). AI can be performed during a natural cycle or with artificial hormone stimulation (ovulation induction).
Artificial Insemination using donor insemination
Donor insemination involves the use of sperm that is ‘donated’ by a person who is not the partner of the woman undergoing treatment. It may be used to artificially inseminate a woman when her male partner has problems with sperm quality or production (i.e he produces poor quality sperm or no sperm at all). It may also be used if there is a high risk of passing on a genetic disease. Artificial insemination using donated sperm is also an option for single women or same sex couples.
More advanced techniques include in-vitro fertilisation, intracytoplasmic sperm injection, and pre-implantation genetic diagnosis. Donor eggs and embryos may also be used in these processes. These techniques are explained below.
In-vitro fertilisation (IVF)
IVF is the name given to any process used to conceive a child outside the body. It involves sperm fertilising an egg in a laboratory, rather than inside a woman’s fallopian tubes. It involves the retrieval of eggs from a woman (usually after having stimulated her ovaries using hormones), and then placing her eggs together in a culture dish with many thousands of sperm (obtained from her male partner or a donor). Fertilisation takes place in the dish, and may result in a number of embryos which are developed in the laboratory over 2-5 days. One or more of the embryos are then transferred into the woman’s uterus (other embryos may be frozen for later use, research or donation).IVF is often the sole means of achieving pregnancy for women whose fallopian tubes are damaged or blocked due to disease.
Intracytoplasmic sperm injection (ICSI)
ICSI involves a single sperm being injected into each egg during the IVF process, using very fine micro-manipulation equipment. As the human egg is one tenth of a millimetre in diameter and the sperm 100 times smaller, this is a very delicate procedure performed by highly skilled embryologists under a microscope.ICSI may be used when a male has been diagnosed with male fertility problems, such as a low sperm count or sperm that are unable to penetrate the egg, and conventional IVF is unlikely to result in fertilisation. It can also be used if the male partner has previously had a vasectomy, or when sperm are not present in the semen and have to be obtained surgically from the male reproductive tract.
Egg donation involves retrieving eggs from another woman to the one who will carry a pregnancy. It involves hormone stimulation of the donor, which is administered through a diabetic-style pen, to stimulate her ovaries to produce more eggs than usual. Blood and ultrasound monitoring takes place to determine the appropriate time for collection. Once this is decided, a trigger injection of hCG (human chorionic gonatrophin) is given to the woman in the evening, to trigger ovulation, and the operation for egg collection occurs 36 to 38 hours later.Treatment with donor eggs is possible if a woman can not produce eggs or her eggs are of low quality. This may be due to age or premature ovarian failure (where the woman has stopped producing eggs). Use of donor eggs may also be an option in cases of recurrent miscarriage, or if there is a high risk of the woman passing on a genetic disease or abnormality to a child. The recipient woman must also take hormone tablets in preparation for the embryo transfer, and for approximately 10 weeks after the embryos have been transferred.
Treatment using donated embryos is also possible if a person or couple needs donor sperm and donor eggs.
Pre-implantation genetic diagnosis (PGD)
PGD involves the generation of embryos via IVF. Once the embryos are formed, one or two cells are screened for a specific genetic or chromosomal disease or abnormality. The screening gives information regarding the genetic status of the embryo, enabling selection of unaffected embryos prior to implantation and before pregnancy is established.PGD is therefore primarily used as a means for reducing the risk of an individual or couple passing on genetic disease or abnormality to their children. It may also be used by women older than 38 or for individuals or couples who have experienced repeated miscarriage or repeated IVF failure.