ICSI (Intracytoplasmic Sperm Injection)


Intracytoplasmic Sperm Injection (ICSI), pronounced “ick-see” is a process where one sperm is directly injected into a woman’s egg to create a fertilized embryo. This is an advanced technique used during an In Vitro Fertilization (IVF) cycle.
IVF is an Assisted Reproductive Technology (ART). The process that leads up to the insemination of eggs with sperm is called controlled ovarian hyperstimulation. This is when a woman’s ovaries are hyperstimulated to produce multiple follicles, each potentially containing an egg. Ovarian hyperstimulation is achieved by giving a woman gonadotropins like Follistim and Gonal-F, while monitoring their estrogen levels and the size of the follicles.
Once the eggs have been retrieved during an in-office procedure called an egg (oocyte) retrieval, it is time for the true IVF to begin. There are two distinct ways an embryologist fertilizes an egg.
The first is conventional insemination, in which eggs are placed in media drops and sperm is then added to those drops. This allows the sperm to penetrate the egg’s zona pellucida (outside shell) and deposit the male’s DNA into the egg’s ooplasm (egg’s cytoplasmic matrix), hopefully resulting in fertilization of the egg.
Secondly, is the more invasive procedure called ICSI where one sperm is directly injected into the center of an egg to fertilize it. Only mature eggs are injected via ICSI, and not all retrieved eggs reach maturity. The polar body indicates that the egg is mature and ready for insemination. Eggs must have all of the protective granulosa cells removed prior to ICSI so that the polar body can be visualized. This process was initially developed for men whose sperm had low motility, and could not penetrate the zona pellucida.
During an ICSI, an embryologist determines what appears to be the best sperm to directly inject into the egg, by looking at the morphology (shape) and progression (forward movement) of the sperm. The sperm are then aspirated from the sperm drop, into a microtool called an ICSI needle. Once the sperm is in the ICSI needle, the embryologist moves it to a media drop containing the eggs. The egg to be injected is held gently in place by a microtool called a holding pipette, which exerts a light suction on the egg, allowing the embryologist to place the egg in perfect injection position. The embryologist then brings the ICSI needle with the sperm down to the other media drop and lines it up with the egg. The ICSI needle is gently pressed into the side of the egg below the polar body. The zona pellucida and oolema (membrane between the egg’s innards and the zona pellucida) are punctured and a small part of the ooplasm is aspirated into the needle to gently mix it before the sperm is placed into the egg. This is the process of fertilization by ICSI.
For both techniques, the eggs are checked the next morning to determine whether fertilization has occurred. ICSI is used at CNY Fertility Center in 99% of cases because it reduces the risk of fertilization failure due to the sperm’s inability to penetrate the egg. However, both techniques are available to our patients.
Questions often arise regarding the safety of ICSI for offspring. The American Society of Reproductive Medicine states that “If a woman gets pregnant naturally, there is a 1.5% to 3% chance that the baby will have a major birth defect. The chance of birth defects after ICSI are rare. Certain conditions that have been associated with the use of ICSI (Beckwith-Wiedemann syndrome, Angelman syndrome, hypospadias, or sex chromosome abnormalities) are thought to occur in far less than 1% of children conceived using this technique. Some of the problems that cause a patient’s infertility may be genetic (their father’s have male factor infertility). Therefore, boys (of men with male factor fertility) conceived with the use of ICSI may have infertility issues as adults.”
ICSI technique fertilizes on average 50-80% of the eggs that are injected, whereas conventional IVF fertilizes around 50% of eggs. After the eggs are determined to be fertilized, they are called embryos. The embryos are maintained in special petrie dishes for the next 2-6 days, allowing cells to divide and grow. Once the embryos reach the proper stage of growth they are transferred back to the female patient’s uterus to establish a pregnancy.
ICSI is an innovative option for family building, giving many couples potential for genetically related children that did not exist before its development. For more information about IVF, ICSI or Conventional IVF ask a staff member at any of our centers.