Zona drilling: A new approach to male infertility

Conclusions and prospects

Zona drilling is a powerful new tool for increasing the efficiency of IVF in animals and humans. The procedure incurs minimal harm to the oocyte and retains potentially selective prerequisites for sperm fertilizability such as motility. The methodology results in fertilization by sperm which have spontaneously undergone the AR, a situation which contrasts with normal fertilization. However, animal studies indicate that this feature does not compromise embryo development and, further, suggest that many potentially normal sperm are excluded from participating in fertilization by virtue of having undergone the AR. This observation not only reveals fundamental characteristics of normal fertilization, but offers encouragement that zona drilling can be used to increase the number of normal live births in both animal and human systems.

In animals, reproductively compromised but otherwise highly valuable genotypes could be rescued by zona drillings. The method might also allow efficient fertilization in vitro in species for which this procedure is currently ineffective. In humans zona drilling clearly can allow previously infertile couples to become pregnant. It also may be useful in enhancing the fertilization rate for oocytes which must be reinseminated. In short, zona manipulation promises to fulfill an increasingly important role in reproductive management of humans and livestock.