IMSI/PICSI - Sperm selection

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In the in vitro fertilization procedure by intra-cytoplasmic sperm injection (ICSI), a single sperm is inserted inside the egg using a thin micropipette. The sperm is selected by the embryologist based on the sperm's morphology, or "look," and motility. Thus, the ICSI method mimics the natural mechanisms of sperm selection during fertilization. Unfortunately, ICSI alone does not allow selection of the sperm in terms of chromatin integrity and/or full maturity. Here, additional techniques used in in vitro fertilization (IVF) laboratories are needed.

IMSI

In the IMSI method, additional magnification is used to select the sperm before fertilization. A special lens and computer software allows you to see vacuoles inside the sperm head, the presence of which correlates with sperm chromatin damage. Sperm without vacuoles, and therefore with a lower risk of chromatin damage, are selected for fertilization.

The IMSI method is non-invasive and does not carry any risks. It is especially recommended to couples in whom subsequent attempts at in vitro fertilization by the ICSI method have failed and to couples with decreased or abnormal sperm parameters. The use of IMSI also increases the chances when the ovarian response to stimulation was unsatisfactory. The low number of oocytes obtained during such a procedure creates the risk that some of them may be fertilized with abnormal sperm. The IMSI method - through the possibility of selecting the best sperm - improves the chance of obtaining correct embryos and thus the chance of the desired pregnancy.

PICSI

The PICSI method takes advantage of the ability of mature sperm to bind to hyaluronan. A sperm that has achieved full maturity is more likely to successfully fertilize an egg.

PICSI fertilization uses a special dish that selects sperm for binding to hyaluronan and, therefore, completed maturation. These "selected" mature sperm are then used for in vitro fertilization. In many cases, this increases the percentage of correctly fertilized oocytes and - thus - the number of embryos, allowing the selection of the most optimal embryo on the day of transfer.