Test tube fertilization (IVF)

When no pregnancy occurs naturally or after IUI, a reason may be that the sperm were unable to reach the oocyte and fertilize it. To be able to monitor fertilization, the researchers in the late 70’ties developed test tube fertilization.

With this method, eggs are cultured in the laboratory and put in a petri dish together with the sperm. The fertilized oocyte (embryo) is then placed in the uterus.

The IVF procedure

This treatment is more demanding for the woman. She needs to be treated with hormones which stimulates growth of follicles in the ovaries. Aspiration of oocytes typically results in 8 to 10 eggs per treatment.

Each oocyte is put in a separate petri dish with approximately 100,000 motile sperm. The sperm is prepared by washing. To be able to fertilize, it is essential that the sperm are able to beat vigorously with their tail and can release enzymes in the acrosome placed on the anterior part of the head. The enzymes dissolve the vestments of the oocyte and aid the process of fertilization.

Development and transfer
A typical procedure in the laboratory results in fertilization and development of approximately 60% of the oocytes. The oocytes undergo cell division and after 3-5 days an embryo is transferred back to the uterus. If all goes well it will implant and continue to grow.

How does sperm DNA fragmentation affect IVF treatment?

Production of energy in a sperm will result in damage (fragmentation) if the DNA is not robust and well-protected. In IVF, the long journey to the oocyte is by-passed but the sperm still needs to complete the exhausting fertilization of the oocyte.

The level of DNA fragmentation (DFI) will affect the out come of the treatment significantly. If DFI is between 15 and 25, the pregnancy chance is approximately halved. When DFI is above 25, the pregnancy chance is only about 10% per IVF treatment.

Sperm DNA fragmentation is a more pronounced problem in IVF
Couples who receive IVF treatment will typically have received IUI treatments to start with. Couples who achieve a successful pregnancy after IUI treatments will more frequently have a DFI below 15. For this reason, the proportion of men with a DFI above is increased when the couples receive IVF treatment.
SPZ Lab data for more than 11,000 couples clearly show that sperm DNA fragmentation is a very frequent problem for couples receiving IVF or ICSI treatments.
Approximately 25 to 30% of the men will have a DFI between 15 and 25.
In addition, 20 to 25% of the men will have a DFI above 25.