Several medical agents were shown to be beneficial when given in the luteal phase of an IVF cycle, but the optimal regimen has not been yet determined. In 2006, a European group reported that addition of GnRH analog (Decapeptyl) as luteal support in IVF cycle significantly improved pregnancy and delivery rates. It is not known whether this positive effect influences the corpus luteum, embryo or the uterus. The researchers sought to evaluate the effect of GnRH administration as luteal support in frozen-thaws IVF cycle.