What is Microinjection?

Microinjection is an assisted reproductive technique specially developed for treating severe male infertility. This method aims to achieve fertilization by directly injecting the sperm into the egg when the sperm lacks normal fertilization capability. IVF and other known treatment methods have low or no fertilization rates in cases of severe male infertility. In cases of low sperm count, motility, or morphological abnormalities, natural fertilization of the egg by sperm is not possible. In microinjection, under a microscope, sperm is injected into the egg retrieved from the female using micro-pipettes. The procedures are performed under the microscope with 200-400x magnification on a heated surface using a micromanipulator.

Who is Eligible for the Microinjection Method?

The microinjection method can also be applied to couples where fertilization cannot be achieved with IVF or where there is an insufficient number and/or quality of sperm and eggs for IVF. The procedure can be performed using semen with very low sperm count or, in cases where no sperm are found in the semen, sperm obtained from the testes can be used. In some men, sperm may not be found in the testes. In such cases, if available, spermatids, which are immature cells that develop into sperm, can be used. However, results obtained using spermatids are not yet fully successful, and fertilization rates are low.

How is Microinjection Performed?

The microinjection procedure is performed under a microscope equipped with specialized equipment, using sterile, single-use glass micropipettes. The eggs obtained after the egg retrieval procedure are cleaned of surrounding cumulus cells to identify mature and usable eggs. A special culture medium containing sperm from the male is prepared in a sterile, non-toxic plastic dish for the microinjection process. Then, microdroplets containing special culture medium for the mature eggs are prepared. The sperm is immobilized by pressing its midpiece with the microinjection pipette. The immobilized sperm is then aspirated into the pipette and injected into the droplet containing the egg. This procedure is applied sequentially to all eggs. After completion, the eggs are transferred to special culture media, and fertilization is checked 18-20 hours later.

In which cases is Microinjection applied?

In cases of severe male infertility, sperm lack the ability to fertilize the egg. Severe male infertility is defined as having fewer than one million sperm with rapid progressive motility and normal morphology. Even when both sperm and egg are completely normal, fertilization may not occur with the IVF method. In cases of unexplained infertility, fertilization fails in 15-20% of IVF attempts. If IVF is applied directly to couples with normal sperm parameters, fertilization failure may occur. Therefore, in couples with a sufficient number of eggs (10 or more), microinjection and IVF methods are used together. This way, eggs are divided into two groups: fertilization is checked by IVF, and microinjection is used as a precaution against fertilization failure.

Although ICSI offers a promising treatment option for male infertility today, the most important factors affecting success are the woman's age and the quality of the retrieved eggs. Factors caused by advanced maternal age and increased chromosomal abnormalities influence the success of male infertility treatment depending on the woman.

What is Embryo Development Monitoring and How Is It Performed?

Ensuring embryo development in IVF treatment is the most important step in laboratory conditions. After fertilization, embryo development is carefully monitored under laboratory conditions and with the guidance of an experienced team, and the transfer procedure is performed at the appropriate time.

Fertilization: Fertilization refers to the fusion of a sperm cell with an egg cell. This process occurs when spermatozoa penetrate the outer membrane of the egg and reach the cytoplasm of the egg cell. As a result of fertilization, a single-celled embryo called a zygote is formed.

Cellular Division: The zygote divides to form more cells. First, the zygote divides into a two-cell embryo, and then cell divisions continue. These divisions result in a multicellular embryo. The first division usually occurs about 24 hours later, followed by cell divisions at regular intervals.

Morphological Changes: The embryo undergoes morphological changes alongside cellular divisions. A regular arrangement forms between the cells, and the embryo divides into groups of cells called blastomeres. At the same time, the embryo becomes a morula, composed of small cells formed by mitotic divisions.

Blastocyst Formation: In the later stages of early embryo development, the morula structure transforms into a blastocyst. The blastocyst contains an inner cell mass (ICM) and a layer of cells called the trophoblast. The inner cell mass serves as the source of cells that will form various organs and tissues of the embryo in later stages, while the trophoblast will develop into cells that form the placenta and supportive tissues during early pregnancy.

Microinjection Method or IVF?

In the microinjection method, the chances of pregnancy and fertilization are higher compared to the classic IVF method. However, success rates vary depending on the condition of the couple.

When is the Microinjection Injection Performed?

The microinjection method is performed after the eggs are prepared following the egg retrieval stage.