How does a natural pregnancy happen?
For pregnancy, the sperm must move from the cervix (narrow and lower part of the uterus) into the uterus and reach one of the fallopian tubes. If sperm reaches the fallopian tube sooner than the egg cell is released from the ovary (ovulation), Sperm and oocytes can combine in the tube, which usually occurs on the side where the ovulation is performed and then pregnancy.
When is ICSI done?
Before the male sperm can fertilize the female egg cell, the sperm head must attach to the wall of the egg cell. After attachment, the sperm penetrates from the outer layer into the egg cell (the cytoplasm) and thus fertility occurs. Sometimes sperm cannot penetrate into the body for many reasons. The outer layer of the egg cell may be thick or hard to penetrate or the sperm motility may be low. In these cases, a procedure called sperm injection into the cytoplasm of the egg cell (ICSI) is performed to help fertilize the egg cell or ovum. At ICSI, a sperm is injected directly into the cytoplasm of the egg cell.
Why ICSI is needed?
ICSI is helpful in the following:
● Male sperms are too small to be sufficient for artificial insemination (IUI) or IVF.
● Sperm motility is not normal
● Sperm have difficulty attaching to the egg cell.
● There is a barrier to sperm movement in the male genital tract, which does not allow sperm to exit.
● Use mature oocytes in the laboratory where IVF is not a suitable method for fertilization of the egg cell, regardless of sperm conditions.
● Egg cells that have been previously frozen are used.
How is the ICSI process?
There are two ways to fertilize an egg cell by artificial fertilization; the traditional method and ICSI. In traditional IVF, more than 5000 sperm is placed next to the egg cell in a laboratory container. Fertility occurs when one of the sperms infiltrates into the cytoplasm of the egg cell. In the ICSI process, a thin needle called a micropipette is used to inject a sperm into the egg cell center. In both traditional IVF and ICSI methods, once fertilized, the fertilized egg cell (now called the embryo) grows in the laboratory for 1 to 5 days before being transferred to the female uterus.