Answer from: Raúl Olivares, MD
The most common way of preparing the sperm and the first thing that we do is washing the sperm sample to remove all the substance. That may cause problems even in the woman’s body because that’s something that is also done when we are preparing the sperm for an IUI. Once we have that sample, what we’re going to do first, is to centrifugate. We are going to get all the sperm and separate all the fluids from the sperms and put those sperm into a so-called gradient of different densities. The first step is a very low-density substance, and as the sperm get deeper into the tube, the density is going to be higher. The idea is that we want to have the so-called pellet, which is a good amount of sperm with good motility and good morphology.
Once we’ve got this, we centrifugate the sample again, and then we perform the selection of the sperm that we are going to inject into the egg. In our case, we work like that because we do ICSI in 100% of the cycles. In the end, what we want is to select one sperm that is going to be injected into each egg. In cases in which conventional IVF is done, that means that you leave the egg with 100 000 sperm to achieve a kind of natural fertilization. The last step can be avoided, and you can just put all the sperm that you have obtained after the gradients and with this amount of 100 000 per egg and see what happens.
What we recommend doing, so that we can avoid low fertilization failures or even a complete fertilization failure sometimes is to do ICSI, which is not harmful. It has not been related to any long-term side effects, and it allows us to offer higher fertilization rates, therefore, more embryos to choose from afterwards.
How sperm is prepared for IVF?
What is sperm preparation? What does washed sperm mean? Sperm washing is a method used for semen preparation for IVF, as well as, IVF with ICSI, IUI. How does it work?