Spermatozoa are ejaculated inn the seminal fluid during intercourse or masturbation. During assisted reproduction the spermatozoa are extracted from the semen by a series of processes - centrifugation and washing, layering (to select the active sperm and leave the immotile or dead sperm behind) or selecting the best sperm by making them swim through a denser medium and using those that succeed.
A
careful evaluation of the number of good active sperm will determine
what can of treatment is possible. Sperm counts can vary from day
to day so frequent sperm analysis is necessary to update the treatment
options particularly w hen the levels are below the red line (20 million
per ml)
Semen samples must be washed prior to being used for IUI, IVF and ICSI techniques. Washing of sperm removes the seminal plasma, dead sperm and other cells.
The decision on the choice of the semen preparation method is based on the history, previous semen analyses as well as an examination of the present sample. Another consideration is whether the fertilisation will be by IVF or ICSI. In IVF you will need more sperm for insemination. The preparation methods select sperm, based on their motility, ideally selecting only live sperm, or on their density, ideally selecting only mature sperm. If the sperm count and motility are adequate, migration (swim-up) and wash is suitable. If semen quality is poor and includes large numbers of other cells, density gradient centrifugation is preferred. Recovery of sperm is more effective using the gradient centrifugation method than using the swim-up procedure, with respect to total yield. However, in some instances per cent motility can be higher in a sperm preparation done by swim-up.