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Once all the eggs are injected with a single sperm each, they are placed in the CO2 incubator, and then observed approximately 14 hours later to see if fertilization has taken place. If fertilization has occurred, the two to four cell embryos can be transferred into the wife's uterus about 48-72 hours after ICSI, as is done for IVF. Interestingly, embryo implantation rates in these patients are quite high, because the wives are usually young and completely normal.
Fertilization rates in the range of 60-80 per cent have been achieved in experienced hands, which means, of 100 microinjected eggs about 60 form embryos after ICSI. In fact the technology is now reliable enough to virtually guarantee fertilization, if there are sufficient good quality eggs. The pregnancy rate in one ICSI cycle is about 35 percent. Remarkably, the chance of achieving a pregnancy does not depend upon the sperm count or number (since you only need as many sperm as there are eggs!), but rather on the number and quality of eggs retrieved, which, in turn, depend upon the woman's age. The risk of having a baby with a birth defect is not increased with this technique.
ICSI is very expensive at present, because of the advanced technology it utilizes. Nevertheless, it is now available in most of India's large cities, and as times goes by, it is hoped that the cost of this procedure will decrease, making it affordable for more patients.
Some IVF clinics have started performing ICSI routinely for all patients, instead of offering them IVF. However, this is inappropriate. ICSI should be reserved for only two groups of patients: (1) those who have severe male factor infertility, for whom IVF is not a treatment option; and (2) those patients whose sperm have not been able to fertilize the eggs in an IVF cycle (total fertilization failure). Remember that pregnancy rates with ICSI are no better than with IVF, as long as fertilization occurs.
ICSI is still a new technique, and even though more than 10,000 babies have been born worldwide after it has come into use, and detailed studies have shown that there is no increased risk of birth defects after ICSI, nevertheless, it should only be reserved for those patients for whom traditional IVF is not a valid treatment option.
It is also possible that some of the male children born as a result of this technique may be infertile as well (for example, if the cause for the testicular failure is a defective genetic locus, such as a micro deletion on the Y chromosome).
However, for some patients with severe testicular failure, sometimes it is not possible to find any sperm at all even in spite of taking multiple testicular biopsies. In such patients pregnancies have been achieved even by injecting round spermatids (immature precursor cells from which the sperm are formed) from the testis into the egg. This is now an area of intense research all over the world.
For men with no testes at all, the only technologic solution today would be cloning using nuclear transfer technology. This involves inserting the nucleus from an ordinary cell of the man (which contains all his DNA) into his wife's enucleated unfertilized egg (the nucleus of which has been removed) and then activating it by electro fusion. While cloning has been performed successfully in many animal species, it has never been used for treating humans so far.
© Dr. Aniruddha Malpani and Dr. Anjali Malpani www.drmalpani.com
Credits: How to Have a Baby: Overcoming Infertility
