The Needle vs. the Dish: Should ICSI Be Used in All IVF?
The introduction of Intracytoplasmic Sperm Injection or ICSI has made it possible to fertilize eggs with sperm derived from men with the severest degrees of male infertility. What’s more, pregnancy rates achieved by this method of fertilization are as high, if not higher, than those of conventional IVF performed in cases of non-male-factor infertility.
ICSI involves the direct injection of a single sperm into each egg under direct microscopic vision and requires a high level of technical expertise. In fact, even when there is an absence of sperm in the ejaculate such as occurs in cases of a) congenital absence of the Vas deferens (when a man is born without these major sperm collecting ducts), b) in cases where the vasa deferentia (ducts that carry the sperm from the testicles to the urethra for ejaculation) are obstructed (such as following vasectomy or trauma), and c) in some cases of testicular failure or where the man has impotence, ICSI can be performed with sperm obtained through Testicular Sperm Extraction (TESE), or aspiration (TESA). In such cases, the birth rate is usually no different than when IVF is performed for indications other than male infertility.
When evaluating all available information regarding the use of ICSI…here is what emerges:
The performance of ICSI for male factor infertility is associated with:
- A slight increase in certain structural embryo chromosomal abnormalities (e.g., deletions).
- A slight increase in the incidence of miscarriages
- A slight increase in the incidence of birth defects
- An increased potential that male offspring will also present with male infertility later in life.
When ICSI is performed for indications OTHER THAN male infertility there is:
- No increase in the risk of subsequent embryo chromosome deletions
- No increase in the incidence of miscarriages
- No increased incidence of birth defects
- No increased potential for a resulting male offspring to be infertile in later in life
It follows that the complications associated with ICSI are likely attributable to the indication for which ICSI is being done (the male factor infertility) rather than with the ICSI procedure itself.
The observation that ICSI, when performed for the treatment of male infertility increases the potential for resulting male offspring to be infertile later in life, suggests that ICSI allows sperm that carry DNA with male factor infertility characteristics to the egg at fertilization.
Given the above, in my opinion, there is really no down side to performing ICSI on all patients undergoing IVF. There are a number of reasons why there is a strong movement afoot to perform ICSI across the board, regardless of whether there is proven sperm dysfunction.
First, it is mandated for the treatment of all cases of male infertility, anyway. Second, as mentioned above, it is not the procedure of ICSI itself that causes complications, but rather the indication for which ICSI is done.
Thus the performance of ICSI across the board should be an acceptable policy. Here are a few points that support this position:
- IVF is associated with unanticipated absent or poor fertilization in 12-15% of cases. In fact, newer tests of sperm function such as the sperm chromatin structure assay (SCSA), have shown that DNA damage may be present in sperm derived from men with both normal and abnormal semen analyses. Undoubtedly, male infertility is present in such cases regardless of whether the semen analysis is “normal” or “abnormal”. Forced fertilization of eggs using ICSI will help couples avoid the disappointment associated with unanticipated failed fertilization that might otherwise occur in such cases.
- Fertilization in the Petri dish requires an interaction between sperm and the cumulus cells that surround the egg. During many IVF procedures, there is a need to remove the surrounding cumulus cells in order to examine its structure, its maturity and to prepare it for preimplantation genetic screening (PGS). Having removed the cumulus cells, the egg is far less capable of being fertilized spontaneously, thus mandating ICSI in such cases.
- In all cases of infertility, whether of female, male or “unexplained” nature, regardless of sperm function, ICSI bypasses most dysfunctions, eliminating the majority of barriers to fertilization. If, in spite of ICSI, fertilization still does not occur, then there is a greater chance of the underlying cause being genetic/chromosomal (involving egg and/or sperm), making the argument for routine ICSI even more compelling.
The proposition for “universal”, use of ICSI is based on a higher fertilization rate than by conventional IVF, the fact that male infertility is often “occult” (not revealed through traditional sperm analyses) , the need to perform ICSI when cryopreserved sperm is used in IVF, and the necessity to do ICSI in all cases of PGD/PGS. However, the most compelling justification might be the fact that the procedure of ICSI itself, apparently does no damage.