Fertility doctors say they have found a non-invasive way to screen In Vitro Fertilisation (IVF) embryos for genetic abnormalities. The current method involves taking cells from the embryo itself, which experts fear may be harmful. Now UK researchers say it is possible to run the same checks on cells surrounding the fertilised egg that are normally thrown away. The test could tell a woman if her baby was likely to have a condition like Down's syndrome. It would not only be less invasive, but cheaper too. Lead researcher Elpida Fragouli, from Oxford University, said: "In the ovary, the eggs are surrounded by a cloud of tiny cells, known as cumulus cells.Dr Fragouli's team examined cumulus cells from 26 women undergoing genetic screening prior to IVF treatment.
They found abnormalities in the cumulus cells that appeared to tally with genetic errors in the eggs they had surrounded. Dr Fragouli added: "We are still in the process of establishing the usefulness of these genes as non-invasive markers of egg chromosome status and quality."However, it is interesting that several of these genes are involved in vital cellular functions of the cumulus cells and egg they enclose, such as cell signalling and regulation, hormonal response and cell death, and so they may shed light on the genetic origins of chromosome abnormality." Putting only one fertilised egg into the womb avoids multiple births, which are known to increase the health risks of both mother and child. (BBC)
About IVF
IVF is the process of fertilisation by manually combining an egg and sperm in a laboratory dish. When the IVF procedure is successful, the process is combined with a procedure known as embryo transfer, which is used to physically place the embryo in the uterus.There are basically five steps in the IVF and embryo transfer process which include the following: Step 1: Fertility medications are prescribed to control the timing of the egg ripening and to increase the chance of collecting multiple eggs during one of the woman's cycles. This is often referred to as ovulation induction. Multiple eggs are desired because some eggs will not develop or fertilise after retrieval. Egg development is monitored using ultrasound to examine the ovaries and urine or blood test samples to check hormone levels.Step 2: Eggs are retrieved through a minor surgical procedure, which uses ultrasound imaging to guide a hollow needle through the pelvic cavity. Sedation and local anesthesia are provided to remove any discomfort that may be experienced. The eggs are removed from the ovaries using a hollow needle, which is called follicular aspiration.
Step 3: Sperm, usually obtained by ejaculation, is prepared for combining with the eggs. Step 4: In a process called insemination, the sperm and eggs are placed in incubators located in the laboratory which enables fertilisation to occur. In some cases where fertilisation is suspected to be low, intracytoplasmic sperm injection (ICSI) may be used. Through this procedure, a single sperm is injected directly into the egg in an attempt to achieve fertilisation. Step 5: The embryos are usually transferred into the woman's uterus anywhere from one to six days later, but most commonly it occurs between two to three days following egg retrieval. At this point, the fertilised egg has divided to become a two-to-four cell embryo. The transfer process involves a speculum, which is inserted into the vagina to expose the cervix. A predetermined number of embryos are suspended in fluid and gently placed through a catheter into the womb.These steps are followed by rest and watching for early pregnancy symptoms. A blood test and potentially an ultrasound will be used to determine if implantation and pregnancy has occurred.
