Intracytoplasmic sperm injection, ICSI, is a proven method of reproductive medicine that has helped many childless couples achieve a desired child. ICSI is now the most commonly used method in artificial insemination.
What is intracytoplasmic sperm injection?
In the ICSI method, a single sperm is actively fused with an egg under microscopic control. Quite different fertility disorders on a physical or psychological level can lead to an unfulfilled desire for children in men and women. Modern reproductive medicine can be very helpful in the case of many fertility disorders, ultimately helping to achieve the often longed-for desired child. The precursor of intracytoplasmic sperm injection is the fusion of egg and sperm in a test tube, better known as in vitro fertilization, or IVF for short. This therefore refers to fertilization outside the body, where fertilization would otherwise normally take place. ICSI is a special form of IVF and has been performed since 1992 after years of preclinical research. So, there are not many adults conceived by ICSI method at present. Intracytoplasmic sperm injection is especially interesting for those couple relationships where the male’s sperm is the cause of the fertility disorder. The sperm quality is insufficient in terms of sperm motility or mobility for natural fertilization. Alternatively, the number of sperm in the ejaculate is significantly reduced so that natural fertilization is not possible. In both cases, the sperm cells do not manage to actively penetrate a single cell on their own. The ICSI method simulates precisely this process by actively fusing a single sperm with an egg under microscopic control.
Function, effect, and goals
Intracytoplasmic sperm injection is now the method of choice for proven impaired male fertility. In so-called obstructive azoospermia, sperm cannot enter the vas deferens from the testis because of an obstruction. In this condition, ICSI cannot be done because there are no sperm in the seminal fluid. A prerequisite for intracytoplasmic sperm injection is always the presence of sperm cells in the seminal fluid, even if there are only a few. Normally, one milliliter of sperm contains millions of healthy sperm cells. With the so-called MESA and TESE procedure, sperm cells are collected directly from the tissue of the testicle or epididymis in cases of obstructive azoospermia. In all forms of non-obstructive azoospermia and oligospermia, i.e. severely reduced number of spermatozoa in the semen, intracytoplasmic sperm injection is the method of choice. Among the few sperm available, the best one for ICSI treatment must be filtered out in the laboratory under a light microscope. Only mobile and anatomically intact sperm are used for ICSI, otherwise fertilization cannot be expected. On the day of the intracytoplasmic sperm injection, the couple must present themselves together at the fertility clinic. The man must make a sperm donation while the woman is prepared for the procedure. Prior to ICSI treatment, the woman is given high doses of sex hormones to better control the day of ovulation. Blood values and the size and maturity of the egg follicles are checked regularly. Once ovulation has been triggered, eggs are retrieved through the vagina. At this point, fresh sperm must also be available, but it is also possible to use a frozen sperm portion for the procedure. Now the actual intracytoplasmic sperm injection takes place under the microscope. For this purpose, a single sperm is introduced directly into the egg using a special glass pipette. The thus artificially fertilized egg is placed in a special nutrient solution for incubation in a warming cabinet at a temperature of 37 degrees Celsius. Only if fertilization is successful, embryos mature there within 2 to 5 days, which can then be transferred through the vagina into the uterus using a fine needle. If an embryo nests in the lining of the uterus and cell division begins, the woman is considered pregnant and the process of intracytoplasmic sperm injection is considered successfully completed.
Risks, side effects and dangers
Not every ICSI is successful; at the latest after several unsuccessful attempts, couples may experience a certain frustration, which can be very stressful psychologically in the long term. The exact mechanisms why some ICSI do not lead to successful pregnancy are currently unknown. Hormonal and genetic influences are suspected. The financial burden on couples of multiple ICSI attempts should also not be underestimated. Government subsidies have been steadily reduced in recent years, so that a large part of the costs must be borne by the couples themselves. Long-term consequences of ICSI cannot be assessed at present. This is because so far there are only a few adults who have been conceived by means of ICSI. However, the newborn ICSI children did not show any abnormalities compared to infants from normal births. The genetic risks cannot be assessed conclusively at present, but the cost-benefit risk of ICSI treatment is nevertheless considered medically justifiable. The average maximum birth rate from intracytoplasmic sperm injections is currently 20 percent. Every effort is being made to further increase this still meager success rate, but this also requires further basic research. In the context of an overstimulation syndrome caused by the hormone administration, the woman may experience serious but reversible side effects. As with natural fertility, the younger a woman is at the time of the procedure, the better she can conceive with ICSI. Another unique feature of intracytoplasmic sperm injection is the possibility of a multiple pregnancy if two or three intact embryos are accidentally transferred.
