IVF and ICSI are methods of sperm fertilization of eggs, which are used in the field of assisted reproductive technologies for the treatment of male and female infertility. Both methods are actively used at the present time, since each of them has its own advantages. The decision on the choice of one method or another is made by the embryologist for medical reasons, as well as at the request of the married couple.
IVF - what is it?
In Vitro Fertilization (IVF) is one of the methods of artificial insemination, which is used to reduce, mainly, female fertility. This technology is used in the presence of normal spermogram indices. For this, pretreated spermatozoa are placed in the environment with oocytes, where natural fertilization takes place. In other words, one of the sperm cells independently reaches the membrane of the egg and fuses with it, resulting in fertilization.
ICSI - what is it?
Intracytoplasmic sperm injection (ICSI) is a fertilization method in which, with the help of special microinstruments, one sperm is injected into one oocyte, selected by the embryologist for several indications (for example, the appearance of the sperm, motility, movement patterns, etc.) Compared with the IVF method , ICSI is a more complex and therefore more expensive technology. However, the use of this method is necessary in case of male and unclear factor of infertility of a married couple, as well as in fertilization of oocytes after cryopreservation and planning of genetic testing of the future embryo.
ICSI and IVF - what is the difference?
The most obvious and important difference between these methods is invasiveness. IVF is an intact method, that is, no additional manipulations are performed with the resulting oocyte and surrounding cells. It is believed that fertilization occurs by the same mechanism as it would occur naturally in the fallopian tube. ICSI is an invasive method, that is, for fertilization, the oocyte is pierced with a needle through which the sperm is injected. However, many studies have shown that no significant differences were found between the two methods in the number of obtained embryos that are promising for pregnancy.
Another difference is that when performing ICSI, only one sperm is injected into the oocyte, while during IVF fertilization this is not strictly controlled, as a result of which there is a possibility that two sperm can fertilize one egg. Such an embryo cannot be transferred into the uterine cavity of a woman, as this can lead to negative consequences. To prevent such a situation, embryos are assessed the next day after fertilization (after 16-18 hours), where embryos with a double set of genetic material (one paternal and one maternal) are selected for further cultivation.
Further manipulations with embryos look the same: embryos are cultivated in a nutrient medium, on the 5th or 6th day, embryos are selected that have grown to the blastocyst stage (only such embryos are promising for pregnancy when they are transferred into the uterine cavity). Then these embryos are either transferred into the uterine cavity or cryopreserved (embryos are frozen for long-term storage in liquid nitrogen). Also, before cryopreservation, you can perform a biopsy of the embryo, that is, pinch off several cells from the blastocyst in order to further test the genetic material of this embryo.
