Decoronization This step allows perfect visualization of the oocytes to determine which ones are mature and select them for ICSI

Importance of the procedure

Role of the ovum and cumulus cells

The mature ovum is the largest cell in the human body. It contains almost everything necessary for the development of new life: cytoplasm, organelles, and nutrient reserves. It matures inside the ovarian follicle, surrounded by a special fluid that protects it and supplies the necessary components. But the ovum is not alone: it is surrounded by cumulus cells that form a delicate white cloud. These cells can be compared to faithful ladies-in-waiting of a queen: they provide the ovum with food, support, and protection.

When the time of ovulation comes, the ovum leaves the follicle and heads towards the uterus via the fallopian tube. During this journey, it is accompanied by cumulus cells, which form a protective barrier and regulate metabolic exchanges. During fertilization, they first prevent sperm penetration, then withdraw to allow sperm access to the ovum. Once fertilization is successful, their role is completed and the cumulus is gradually discarded. The formation of the connection between the embryo and the maternal organism takes center stage.

Corona radiata – radiating crown

The layer of cumulus cells closest to the ovum forms a dense ring around it, called Corona radiata, “radiating crown”. It protects the ovum against damage and regulates the exchange of signals and nutrients. Additionally, the Corona radiata acts as a filter, ensuring selective contact with spermatozoa.

In the case of natural conception, this barrier is part of the selection mechanism. But in the conditions of a IVF laboratory, the situation is different. In the ICSI (intracytoplasmic sperm injection) technique, the embryologist must work directly with the ovum, and cumulus cells pose an obstacle.

Decumulation procedure

To prepare the ovum for ICSI, decumulation is used. It involves removing the cumulus cells. They are connected by a kind of “glue” based on hyaluronic acid. To destroy these links, hyaluronidase enzyme is used. It breaks down the hyaluronic acid fibers, making the cells less connected. Then, the embryologist uses a micropipette to isolate the ovum and prepare it for sperm introduction.

This is a delicate procedure that requires experience and concentration. The laboratory environment must be calm, as it is precisely the precision and focus of the specialist that determine the success of future fertilization.

Importance of decumulation in IVF and ICSI

Decumulation is necessary not only to facilitate the ICSI procedure but also for diagnosis. Removing the cumulus cells allows assessment of the ovum’s maturity (presence of the polar body), its cytoplasm, and membranes. It is sometimes at this stage that causes of previous IVF failures are identified.

Moreover, decumulation increases the chances of successful sperm injection. Without it, the ICSI procedure is impossible. It is therefore a key step that influences the efficacy of the program.

IVF and donor programs

In vitro fertilization (IVF) is the main infertility treatment method, and decumulation is part of ovum preparation. In ovum donation IVF programs, quality decumulation of donor oocytes is particularly important for selecting mature oocytes. This increases the chances of successful fertilization and embryo development.

In double donation IVF protocols, where both donor eggs and sperm are used, decumulation also plays a significant role. It ensures precise handling of the oocytes and creates optimal conditions for proper embryonic development.

Role of residual cumulus cells

Sometimes, after decumulation, a small amount of cells remains around the ovum. They do not interfere with the ICSI procedure and do not affect the subsequent development of the embryo. Some specialists note that the presence of residual cells may even support biological balance.

Perspectives and importance for reproductive medicine

Decumulation combines knowledge of ovum structure, biochemical mechanisms of cell interaction, and modern embryology technologies. The quality of its execution is directly linked to fertilization and implantation outcomes.

Today, next-generation micromanipulators and advanced enzymatic solutions are used, allowing faster and more precise work. This increases the chances for couples undergoing fertility treatment to have a child.

Importance of the procedure

Decumulation is a key step in preparing the ovum for artificial fertilization. It allows the embryologist to work directly with the cell, evaluate its quality, and perform ICSI with maximum precision. This process combines biology, medicine, and expertise, paving the way for creating new life and increasing pregnancy success rates.