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Inside the lab - why sperm matters

Inside the lab – why sperm matters

By Dr Jennifer Rayward, Co-founder of the ProcreaTec, Madrid

When evaluating male fertility, a sperm analysis is performed. Different parameters like the volume of the ejaculate, motility, sperm concentration and morphology are assessed. Furthermore, at times a test called Sperm DNA Fragmentation is performed.

This diagnostic technique is complementary to sperm analysis and determines the amount of DNA fragmentation in the sperm. DNA fragmentation is the most frequent DNA anomaly present in the male gamete and is associated with lower fertilization rates, poorer embryo quality and lower implantation rates.  An embryo is composed of DNA originating from an egg and a spermatozoon. When the DNA from both gametes is intact, the subsequent embryo will result in a healthy human being. If the DNA is damaged in either the egg or the sperm, reproductive development may be hindered. 

First IVF magazine
15 articles about IVF and Donor Conception by top IVF experts worldwide!

 An embryologist can never improve the sperm in the ejaculate, but at present, we have the possibility, through different technologies, to optimize the embryologist’s chances of selecting the best spermatozoa for microinjection or ICSI (Intra-Cytoplasmatic Sperm Injection).

Before deciding which technology is to be used, the embryologist the sperm analysis the patient has undergone is studied to determine which technique is the appropriate one. Currently, we use three techniques:

  1. PICSI or Physiological Intracytoplasmatic Sperm Injection is the physiological selection of sperm on account of their affinity for hyaluronic acid. Hyaluronic acid is found in the granulosa cells that surround the egg. The sperm is introduced onto a plate and the sperm cells that bind to the hyaluronic acid are selected for microinjection.
  2. MACS or Magnetic Activating Cell Sorting is a technique where magnetic microspheres coated with Annexin V (a protein than binds to sperm cells with loss of membrane integrity) make an immunomagnetic extraction of sperm cells which are apoptotic i.e. the sperm cells that are programmed to die and will not fertilize the egg. Healthy sperm cells do not bind and can be chosen for microinjection.
  3. Fertile Chip is a technique which permits sperm selection based on motility because sperm cells that have double-stranded DNA fragmentation have a characteristic way of swimming. The technique consists of a chip with two holes or chambers connected by a microfluid canal. The sperm that achieves passage through the canal are the ones used for microinjection.

It is important to state that sperm samples can vary. Sometimes the sperm from a patient is slotted for one technique, but when the embryologist assesses the ejaculate on the day of the egg retrieval, she/he might decide to change techniques. For example, when the sperm sample has a low number of sperm cells, PICSI is usually the technique chosen. If the sperm of the patient has been analyzed with double-strand fragmentation, the technique used will be Fertile Chip.

Sometimes the sperm does not appear to be challenging, but the result in a first cycle is for example fertilization failure using conventional ICSI or poor embryo development. In the second cycle, PICSI may be indicated by the lab team to obtain better results in fertilization and embryo development.

Ever since the birth of the first IVF baby, Louise Brown, huge advances have been made in IVF labs all over the world. As specialists in Reproductive Medicine, we must strive to improve our techniques with the objective to help attain the highest pregnancy rate and above all create healthy babies. These sperm techniques are part of this pursuit of modern assisted reproduction to realize these goals. 

IVF-Spain Madrid is one of the leading fertility centers in the world. More information can be found on their website

Editorial Team
Editorial Team
Fertility Road aims to inform and inspire in a way that is direct, honest and empathetic, whilst breaking down the science by being written by top experts from the fertility field.

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15 articles about IVF and Donor Conception by top IVF experts worldwide!