IN VITRO FERTILIZATION (IVF)
What is it? It is a medical process whereby mature eggs are extracted from a woman’s ovaries and fertilized in a laboratory using healthy sperm donated by a man. The fertilized egg is called an embryo which is implanted back into the women’s uterus, creating a pregnancy.
“In vitro” is Latin and literally means “within the glass”, which is understood today as “in a laboratory” setting. This is why children conceived this way are sometimes called “test tube” babies—actually the container used is called a petri dish! Normal conception occurs “in vivo” i.e. “within the living”.
How is it done? Conception, which seems so easy, is actually an intensely complicated process but the IVF procedure can be simplified:
- The couple undergo various health checks
- The woman takes prescribed fertility drugs to create extra eggs (oocytes)
- The growth of the oocytes is monitored by ultrasound
- At the correct time the woman will receive an injection of hCG (human chorionic gonadotropin) to trigger the ovarian follicles to release the oocytes
- Thirty six hours later they will be removed from the ovaries by an ultrasound–guided needle, via the vagina, and they will be placed, in a petri dish culture, to mature for a few hours
- Fresh sperm from the donor is collected by masturbation and placed in the dish
- If fertilization occurs the embryos are allowed to grow for 2 – 5 days
- One or two of the embryos are then implanted into the endometrial tissue of the uterus
- A pregnancy should follow.
Unfortunately, an agonising two weeks also follows as it is only possible to confirm a pregnancy two weeks after the procedure. A blood test is the most accurate way of confirming a pregnancy.
When is it used? It is used as a last option to treat infertility where other options have failed. There are many causes of infertility. In women there can be fallopian tube damage, ovulation disorders, endometriosis and problems inside the uterus, while men can develop various forms of sperm dysfunction. IVF can also be used to circumvent a tubal ligation for a couple now wanting children. The latest research indicates that it can also be used to correct genetic disorders as well. Harvested eggs and embryos can be frozen for later use in cases where fertility could be at risk, for instance, during prolonged cancer treatment.
INTRACYTOPLASMIC SPERM INJECTIONS (ICSI)
What is this? This is used in conjunction with IVF where a fertility problem is caused by a lack of healthy sperm from a male partner. In a laboratory, one sperm is selected and injected directly into the centre of a mature egg, which is then implanted into the uterus. If a suitable sperm is not ejaculated a few can be collected from the tube that stores the spermatozoa (epididymis) or testicle; this is done under a local anaesthetic with the surgeon using a fine needle. ICSI bypasses the natural process in which the sperm is selected and there is a faint chance that, although the sperm is isolated as healthy, a genetic abnormality might be passed on to the child.
When is it used? In cases where IVF fails, the sperm count is low, there are problems with ejaculation or the male partner has had an irreversible vasectomy or injury.
An intracytoplasmic morphologically-selected sperm injection (IMSI) is a variation which uses a microscope with a very high magnification to improve the sperm selection which will rule out genetic problems that might be inherited.
PHYSIOLOGICAL INTRACYTOPLASMIC SPERM INJECTIONS (PICSI)
What is this? In a strange “return to nature” strategy a PICSI is a more technologically advanced process that closely mimics the way an egg will select the sperm in vivo i.e. in natural fertilization.
How is it done? The strongest sperm with the best genetic material suited to fertilization has a receptor which binds strongly to hyaluronic acid which surrounds the egg. The PICSI petri dish is dotted with hyaluronan and the prime sperm will attach to these dots allowing the technologist to select only the most promising to fertilize the harvested eggs. This proof of motility and ability to function obviously improves the chances of creating a viable pregnancy at the end of the procedure…a procedure that is costly for every hopeful couple. Costly, both in money and emotional energy.
Comparisons of the success rates between ICSI and PICSI are being complied but, at the present time, the jury is still out.