Intra cytoplasmic sperm injection
ICSI differs from IVF and natural conception in the following way:
In nature, following ovulation and intercourse, the sperm and the egg meet in the Fallopian tubes and the sperm breaks through the wall of the egg in an attempt to “become one with it” (fertilise it to make an embryo). In IVF, the egg and sperm are taken from the body and put into a special liquid called media. This liquid is made to contain all the substances that is present in the liquid found in the Fallopian tube naturally. The egg and sperm in the mixture are kept at body temperature, in an incubator within an exceptionally sterile environment and left there overnight to allow the sperm to naturally break through the wall of the egg and fertilise it.
Intra Cytoplasmic Sperm Injection (ICSI) on the other hand involves direct injection of sperm into the eggs by a skilled embryologist with specialised laboratory equipment – the cytoplasm being the inside of the egg. This has to be done when the sperm quality and motility is extremely poor and it is anticipated that the sperm will not penetrate the outer capsule of the egg. It can also be done when few eggs are retrieved in an attempt to minimise a unrecognised sperm factor from further diminishing the number of fertilised embryos achieved in that cycle.
How Is ICSI Performed?
There are basically five simple steps to ICSI which include the following:
- The mature egg is held with a specialised pipette
- A very delicate, sharp and hollow needle is used to immobilise and pick up a single sperm
- The needle is then carefully inserted through the shell of the egg and into the cytoplasm of the egg
- The sperm is injected into the cytoplasm and the needle is carefully removed
- The eggs are checked the following day for evidence of normal fertilisation
Once the steps of ICSI are complete and fertilisation is successful, the embryo transfer procedure is used to physically place the embryo in the woman’s uterus via the cervix. No sedation or anaesthetic is required and the procedure is essentially painless.
At the Embryo transfer, a fresh or frozen embryo can be transferred. Usually two embryos are transferred at a time unless only one is available. Sometimes a case may be made for three to be transferred if repeated attempts have failed i.e. recurrent implantation failure or possibly in the case of advanced maternal age and poor pregnancy prognosis. The more embryos one transfers, the greater the risk of multiple pregnancy. This is best avoided due to the increased risk of complications for the mother and babies in higher order pregnancies. The patient will be given medication to support the lining of the womb for 12-14 days following the embryo transfer. It will cause pregnancy-like symptoms. A blood test 12-14 days later is the earliest and most reliable way to confirm a pregnancy. An ultrasound two weeks later will be able to detect a pregnancy sac with a fetus and fetal heart beat. Prior to this, even in the presence of a positive blood pregnancy test, a pregnancy scan is all that may be seen as the fetus is invisible until, two weeks after the positive pregnancy test. The medication given after the transfer to support the lining of the uterus (progesterone gel or pessary) is continued to 10 weeks of pregnancy if the patient is pregnant.
Pre Implantation Genetic Screening – PGS
This refers to removing a single cell from a Day 5 embryo when it has reached the blastocyst stage. This requires a specially trained embryologist and the use of a laser beam. The embryos are labeled very carefully as are the specimens taken from them. The specimen is sent to a genetics laboratory. The chromosomal make up of the embryo can be determined and abnormal embryos are discarded and only normal embryos will be transferred. Taking one cell away from the embryo will not cause it or the resulting baby any harm.