How does fragmented Sperm DNA influence fertilization and embryo development


How does fragmented sperm DNA influence Fertilization and Embryo Development?

The role of male factor infertility on embryo development is gaining attention since the introduction of ICSI as a treatment option for patients with very poor sperm characteristics. In the past, medical decisions on treating infertile couples were based by and large on the results of conventional semen analysis, assessing sperm concentration, motility, and morphology in one or multiple semen samples.

In the early days of ART, severe male factor infertility yielded exasperating results, in the form of meager fertilization and poor pregnancy rates. With preliminary reports on ICSI (intracytoplasmic sperm injection) in the early 1990s, embryologists believed a solution had been found to all cases of male factor infertility.


Nevertheless, unsuccessful treatments despite use of ICSI have indicated that some additional factors may also be involved, including sperm DNA fragmentation or sperm morphologic damage unnoticed by standard intensification used in conventional ICSI. Of late, several techniques designed to improve sperm selection for conventional ICSI have confirmed to increased fertilization rates, improve embryo quality after successful fertilization, and thereby increased pregnancy rates.
Semen quality is usually expressed in terms of sperm concentration, motility, and morphology. Such parameters, specifically morphology and motility, are closely related to DNA variations. Though sperm DNA damage is not considered in regular sperm analysis, sperm DNA damage produces relevant impact on male fertility. But, assisted reproductive technologies have augmented the possibility of anomalous spermatozoa being used to fertilize oocytes. Sperm DNA fragmentation is an important parameter of sperm quality that can be used to assess sperm nuclear integrity, which plays a crucial role in fertilization and embryo development.

Sperm DNA fragmentation had a negative correlation with blastulation and pregnancy rates even with good quality oocytes. High DNA damage levels promoted embryo arrest and induced the activation of apoptotic machinery.

How sperm fragmentation affects pregnancy ?

Research findings suggest that men above 35/40 years have lower sperm count, and less motile sperm which lead to miscarriages when their partners gets pregnant. Body mechanism of these men are not capable of detecting and destroying the damaged or fragmented sperm in their body. Damaged sperms or sperm fragmentation drastically reduce the chances of causing pregnancy, which even lead to birth defects in the babies if pregnancy happens. Reasons for sperm fragmentation are many. For example, a man’s body mass index can also lead to sperm fragmentation if he is obese. Increasing age is also one of the contributory causes. There are some other factors responsible for sperm DNA fragmentation such as lifestyle habits like smoking, alcohol and some clinical causes like varicocele, any infection such as Urogenital infection, due to some occupational pollutants, increase in testicular temperature may also lead to unexplained infertility, implantation failure in in-vitro fragmentation (IVF) coupled with intermittent miscarriages.
There are different factors which lead to sperm fragmentation as explained above. But there are also unexplained causes for infertility in men, which are yet to be explored. Slight damages are normal in the sperms of men, who are fertile even otherwise. Nevertheless, in the event of high sperm DNA damage, then the couple’s chances of getting pregnant are shortened even with the various ART treatments. Therefore, it is essential to know how sperm fragmentation affects pregnancy because it plays a major role in successful conception and most importantly in continuing the same at the earlier stages of pregnancy. If you are experiencing difficulties conceiving, there is a very high probability that sperm DNA fragmentation is the reason behind this. In such situations, a sperm DFI test is the most recommended option to detect sperm fragmentation, which need to be carried out in an andrology laboratory, who do such tests exclusively. There are many different Sperm DNA tests available, but the SCSA® test is the only standardised and best method to accurately determine levels of sperm DNA fragmentation in a semen sample. Andrology Center offers the SCSA® test for Sperm DFI testing in India.

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