Deficiency in Fertilization
What Is Insufficient Fertilization, How Is It Overcome?
On the other hand, fertilization rate decreases in some specific cases due to sperm structure. The major procedures used in this group are microinjection procedures performed with nonmotile sperms. It is obvious that a motile sperm is alive and has a potential to fertilize the oocyte. A nonmotile sperm is nonmotile because it is dead or paralyzed. A paralyzed but living sperm can fertilize the oocyte. However a dead sperm will not fertilize the oocyte. The difficulty here lies in the fact that it cannot be understood whether the nonmotile sperm is alive or dead. Although there are several tests to differentiate that, the sensitivity is low.
Another characteristic of sperm that causes problems with fertilization is ‘Globozoospermia’. It is caused by a structural, enzyme deficiency in the head portion of sperm. Because of that, sperm cannot hold onto, drill through, get in and fertilize oocyte. Unfortunately, the results are similar for microinjected, in other words injected globozoo sperms into the oocyte. In these cases, the sperms that have a normal structure are collected as much as possible and the procedure is carried out with them. While it is very possible to obtain successful results and to achieve pregnancy in men with low rate of globozoospermia, it is difficult to obtain good results in men with high rates of globo, even if the procedure is carried out with sperms that have normal structure.
If any indication of miscarriage is known in advance, it is possible to fix it by using some substances. Substances such as Ca ionophore, strontium etc. are added to the oocyte feeding medium of these patients, or piezzoelectric is applied. It is also cautionary to obtain low fertilization rates in a previous IVF treatment.