"hCG priming" effect in controlled ovarian stimulation through a long protocol

Patients with a history of at least one previous unsuccessful ICSI cycle were randomly assigned into two groups to receive treatment with either a long protocol with rFSH (control group) or a long protocol with rFSH and pre-treatment with hCG (hCG group). In particular, in the latter group, a fixed 7 days course of 200 IU/day hCG was administered as soon as pituitary desensitization was confirmed.The mean number of oocytes retrieved was not significantly different between the two treatment groups, although the percentage of mature oocytes tended to be higher but not significantly different in hCG-treated patients. The percentage of patients with more than one grade 3 embryos was higher in the pre-treatment group, which also showed a higher pregnancy rate.All the above clinical observations, in conjunction with previous data, suggest a point towards a beneficial "hCG priming" effect in controlled ovarian hyperstimulation through a long GnRH-a down-regulation protocol, particularly in patients with previous ART failures.Ovarian response to gonadotrophins varies considerably among women. The importance of this differential response in women with previous ART (IVF/ICSI) failures has prompted researchers to investigate and determine the factors that are implicated [1].Though, follicular development up to the preantral stage is feasible in the absence of LH, an essential role for this gonadotrophin for antral formation as well as further growth and differentiation has been uniformly recognized. LH plays a key role in both oocyte and follicular cells development through modification of the steroid and protein micro- and macroenvironment [2,3]. These physiologic changes have a prominent role in oocyte, maturation, the process of ovulation, and subsequent fertilization and implantation [4].It is well known that LH acts synergistically with FSH in the process of follicular growth: FSH plays a crucial role in recruitment, selection and dominance, while LH contributes to domina