Physiological Intracytoplasmic Sperm Injection (PICSI)

PICSI is a modified version of ICSI (intracytoplasmic sperm injection), which allows to select mature sperms based on their ability to bind to hyaluronan hydrogel. Hyaluronan is the main component of the layer known as cumulus oophorus, which surrounds the oocyte. The head of a mature sperm carries a hyaluronan-specific receptor that enables the sperm to bind to hyaluronan. An immature sperm, on the other hand, is incapable of this bonding.

Since mature sperms manifest high DNA integrity and normal chromosomal aneuploidy frequency, they facilitate parental investment in the zygote that is comparable to sperm selection with the aid of the zona pellucida in the course of natural conception.

PICSI is recommended to couples in the following cases:

  • Repeated unsuccessful embryo transfers;
  • Previous ICSI failure, including post-ICSI low fertilisation rate (less than 30% of fertilised eggs);
  • Teratospermia (spermiogram shows less than 4% of normal sperms);
  • Poor embryo quality, halted or retarded embryo development in previous IVF cycle;
  • Recurring miscarriages.