This technique is used when normal methods of attempted CONCEPTION or ARTIFICIAL INSEMINATION with healthy SEMEN have failed. In the UK, assisted conception procedures are governed by the Human Fertilisation & Embryology Act 1990, which set up the Human Fertilisation & Embryology Authority (HFEA).
This allows regulation monitoring of all treatment centres to ensure that they carry out treatment and research responsibly. It covers any fertilisation that uses donated eggs or sperm (called gametes) – for example, donor insemination or embryos (see EMBRYO) grown outside the human body (known as licensed treatment). The Act also covers research on human embryos with especial emphasis on foolproof labelling and immaculate data collection.
It inspects and licenses centres carrying out fertilisation treatments using donated eggs and sperm. It publishes a code of practice advising centres on how to conduct their activities and maintains a register of information on donors, patients and all treatments. It also routinely reviews progress and research in fertility treatment and the attempted development of human CLONING. Cloning to produce viable embryos (reproductive cloning) is forbidden, but limited licensing of the technique is allowed in specialist centres to enable them to produce cells for medical treatment (therapeutic cloning).
In this technique, the female partner receives drugs to enhance OVULATION. Just before the eggs are released from the ovary (see OVARIES), several ripe eggs are collected under ULTRASOUND guidance or through a LAPAROSCOPE. The eggs are incubated with the prepared sperm. About 40 hours later, once the eggs are fertilised, two eggs (three in special circumstances) are transferred into the mother's UTERUS via the cervix (neck of the womb). Pregnancy should then proceed normally. About one in five IVF pregnancies results in the birth of a child. The success rate is lower in women over 40.
In women with severely damaged FALLOPIAN TUBES, IVF offers the only chance of pregnancy. The method is also used in couples with unexplained infertility or with male-factor infertility (where sperms are abnormal or their count low). Women who have had an early or surgically induced MENOPAUSE can become pregnant using donor eggs. A quarter of these pregnancies are multiple – that is, produce twins or more. Twins and triplets are more likely to be premature. The main danger of ovarian stimulation for IVF is hyperstimulation, which can cause ovarian cysts. (See OVARIES, DISEASES OF.)
Another method of helping infertile couples. In over half of women diagnosed as infertile, the Fallopian tubes are normal, and in many it is unknown why they cannot conceive – although some have ENDOMETRIOSIS.
Eggs are obtained and mixed with the partner's semen, then introduced into the woman's Fallopian tubes for fertilisation to take place. The fertilised egg travels to the uterus where IMPLANTATION occurs and pregnancy proceeds. A variation of GIFT is zygote intrafallopian transfer (ZIFT) in which early development of the fertilised eggs happens in the laboratory before the young embryo is transferred to the Fallopian tubes. GIFT is best used in couples with unexplained infertility or with minor degrees of male or female cervical factor infertility. (See also ARTIFICIAL INSEMINATION.)