GnRH agonists and in vitro fertilization.

GnRH agonists (GnRH-a) were introduced into in vitro fertilization (IVF) superovulation regimens in the late 1980s and have become established as a component of standard regimens in most centers worldwide. Each style of GnRH-a regimen (long, short or ultrashort) is associated with particular advantages and disadvantages. In general the "long protocol" approach tends to be the most widely used. The pros and cons of these different approaches are discussed, as are issues concerned with the management and safety of GnRH-a regimens in IVF.