During the IVF procedure, eggs are retrieved for fertilization but no guarantees are given regarding the number of eggs collected that will become fertilized and out of the fertilized eggs, how many will become embryos. In addition, it is not guaranteed that all of the embryos re-introduced to the woman’s uterus, will manage to implant themselves into the uterus walls and develop into a full pregnancy.
IVF treatment has enabled couples to conceive that would never have been able to without IVF technology. Follicles are fluid filled sacs that each contain immature egg cells that must battle to become mature eggs. During egg collection the fluid in the follicle must be retrieved and at this point it is not known how many eggs has been collected. It is only after the embryologist has removed any debris and cumulus cells from the fluid, that the amount of usable eggs can be determined.
The strongest follicle will become matured attracting the most follicle-stimulating hormone or FSH which is secreted by the pituitary gland. In a normally functioning reproductive system, the matured follicle will burst open and release one egg whilst the other unsuccessful follicles die. Prior to the egg collection procedure during IVF treatment, the patient is administered hormone treatment to stimulate more than one follicle into maturity. The average number of eggs retrieved during IVF is between 5 and 20. The average number of eggs collected during IVF will also depend on how successful the hormone treatment has been in maturing the follicles. Once the follicle fluid has been removed it will be examined to ascertain which ones contain viable eggs.
After collection, the eggs are introduced to the sperm in a specially prepared test tube environment and left to incubate. Only those fertilized embryos will be injected back into the uterus for implantation to occur. The average number of eggs fertilized during IVF will depend very much on the quality of the sperm introduced and whether or not ICSI was used to fertilize the egg. ICSI or Intracytoplasmic Sperm Injection involves the injecting of a single live sperm cell into the centre of the matured egg. The intention is that as many mature eggs are encouraged to develop by fertility medications and will each be removed and injected with a single live sperm. It has been reported that fertilization rates can be between 70 to 80 percent of all the eggs injected.
At Clinic Compare we aim to provide advice and pricing information for anyone interested in these procedures and services.