Outcome of cryopreserved pronuclear oocytes obtained after ovarian stimulation with either HMG or recFSH and the GnRH-antagonist cetrorelix.

The present retrospective study evaluated the outcome of frozen-thaw cycles with oocytes obtained either during a multiple dose protocol of cetrorelix, or after the use of a gonadotrophin-releasing hormone (GnRH) agonist. A total of 101 subfertile couples were included. These couples had a total of 222 transfers of frozen-thawed pronuclear oocytes after IVF/intracytoplasmic sperm injection (ICSI) treatment. According to the stimulation protocol during various cycles, four groups were established: cetrorelix/recombinant FSH (recFSH) (69 cycles), cetrorelix/human menopausal gonadotrophin (HMG) (10 cycles), GnRH-agonist/recFSH (71 cycles) and GnRH-agonist/HMG (72 cycles). The transfer cycles were mildly stimulated with transdermal oestradiol. No statistically significant difference was seen among the four groups regarding post-thaw survival rate, cumulative embryo score, implantation rate and pregnancies. Frozen-thawed pronuclear oocytes obtained with the use of cetrorelix give satisfactory implantation and pregnancy rates, similar to those obtained with a GnRH-agonist. These results do not depend on the gonadotrophins (HMG or recFSH) used in the collecting cycle.