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Sperm Preparation

The aim of washing and preparation of the sperm is to separate sperm from seminal plasma, remove bacteria and other debris and chemicals that may cause infection and irritation. This improves sperm capacitation (this helps increase sperm`s ability to penetrate and fertilize an egg).

Sperm can be extracted from seminal plasma by a number of different methods. The 'Swim up' technique and density gradients are most commonly used. The swim up technique separates the good motile sperm by allowing them to 'swim up' into a layer of sterile culture medium. Following which they are centrifuged and re-suspended in a clean sterile medium (sperm wash). Density gradient separates normal live sperm from seminal plasma and other cells and debris by centrifugation on a layer of fluid containing particles that acts as a filter. The normal sperm become concentrated at the bottom of the layer and can then be removed and 'washed' by centrifugation and re-suspended in clean medium.








There are 2 different procedures which are used to achieve fertilisation

In Vitro Fertilisation (IVF)

Following egg retrieval, the follicular fluid is immediately transferred to the adjacent laboratory for identification of eggs, evaluation, and preparation for insemination. If IVF is being performed, about 3-8 hours later, between 20000-30000 sperm are mixed with each egg in a drop of specially prepared culture medium in a labelled dish. This dish is then kept in the incubator to allow fertilization to occur as they incubate overnight under controlled laboratory conditions.

If the sperm and egg are normal, about 60-70% of the eggs collected will be fertilized. About 5-10% of couples will not achieve fertilization of any eggs. This could be due to sperm lacking the fertilizing capacity or poor egg quality. If fertilization does not occur, the eggs have to be discarded and the remainder of the procedure cancelled. The patient then has to undergo the ICSI procedure in the next cycle. To avoid such disappointments, in select cases, we recommend that half the eggs undergo the IVF procedure and half the eggs the ICSI procedure.


Intra-Cytoplasmic Sperm Injection (ICSI)

This procedure, also known as Sperm Micro Injection, was developed to treat male factor infertility.There are selected groups of patients to whom intracytoplasmic sperm injection (ICSI) is recommended.

  • Men with abnormal sperm parameters e.g. low count, poor motility, high percentage of abnormal forms and high levels of antisperm antibodies in the semen.
  • Couples who have had failed or very poor fertilization following standard IVF treatment.
  • Sperm obtained by electro ejaculation.
  • Frozen sperm
  • Azoospermic men who have a complete absence of sperm in their ejaculate. These men have to have their sperm surgically retrieved


Fertilization rates are in the region of 60-70% of the injected eggs and cleavage rates of about 80% are expected after ICSI. The risk of complete failure of fertilization is less than 5%. ICSI is generally not successful when used to treat fertilization failure that is primarily due to poor egg quality.

The early stages of ICSI are the same as for standard IVF. The eggs, after they are aspirated are placed in the incubator for a period of time usually between 3-6 hours. The eggs are then removed from the incubator and the cells that surround the egg are stripped off to assess the maturity of the egg, because ICSI can only be performed on mature eggs.

Sperm collected from the ejaculate, frozen semen sample or aspirate from the epididymis (PESA) or testes (TESA) is prepared using special cultured medium. Sperm of virtually any quality and from any level of the male reproductive tract may be used with the only criterion for use being that the sperm is alive even if it is not moving (immotile).

Once the eggs have been selected, a chosen sperm is rendered immotile, then sucked into the tip of a very fine glass needle and injected directly into the egg. The egg is held in place by gentle suction on the opposite side using a holding pipette. This is a very delicate procedure and involves using a micromanipulator. This process is repeated for each egg. The elastic nature of the egg membrane means that the tiny hole made by the needle closes very quickly. About 5% of the injected eggs may be damaged by the procedure


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