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STEP — Short Term Ejaculate Preservation

As a more delicate to the cell structure and also more efficient alternative to long-term freezing (-196°), there was developed the short-term non-freezing preservation system, which allows to preserve extracted sperm cells at +4° C temperature for up to 14 days. STEP has been observed to produce sperm more viable and of higher quality than those preserved with deep freezing. The major advantages of short-term preservation are:

  • Lack of damaging impact on the cell membrane
  • Lower cell fragmentation rate in spermatozoa.

Among other research aimed at examining the efficiency and possible side effects of STEP, the reproductive laboratory of University of Hawaii has shown that the method is genetically safe.

The progressive short-term sperm preservation technique was first introduced by a group of reproductive specialists of Yokohama University in 1996. MAMA Clinic was the first fertility institution in Russia to implement it and adopt into clinical practice. Since then, MAMA Clinic specialists have partially modified the method and presented a newer version of it at the Annual ESHRE Meeting in Amsterdam in 2009. The corresponding article was published in “Reproductive Problems” Magazine in volume 5 of 2009.

Another practical advantage of the application of STEP technique at MAMA Clinic is the fact that our patients have gained the opportunity to deliver sperm material on a convenient day prior to its usage for IVF procedure (that is, up two weeks earlier).


Julia Zaikova

Anesthesiologist