GnRH antagonist does not prevent premature luteinization and ovulation in stimulated cycles with gonadotropins for IVF: two case reports.

The use of GnRH antagonists (GnRHant) is increasing in the ovarian stimulation protocol. Among several other benefits, GnRHant should prevent a premature luteinization and premature ovulation, the first described either as a 'reassuringly rare event' or 'frequent event', while the second as occurring more frequently in women with decreased ovarian reserve, advanced age and poor ovarian response. Two cases of associated premature luteinization and premature ovulation, during treatment with gonadotropins and GnRHant in IVF cycles, are here reported. In both cases, premature luteinization occurred and ovulation took place during ovarian stimulation protocols with exogenous gonadotropins and GnRHant, before reaching the criteria of hCG administration, regardless of the age of the patients and their ovarian reserve. Ovulation was documented by the disappearance of most of the developing follicles, by the transformation of endometrium from a triple line picture into a uniform hyper-echogenic image, by the presence of fluid in the pouch of Douglas, by the increase of progesterone plasma levels and the simultaneous reduction of estradiol plasma levels. This evidence can be important for a correct counseling with infertile patients in preparation for an IVF cycle.