Switching from cetrorelix to dydrogesterone in an IVF cycle - a new strategy for unexpected freeze-all cycles.

Preventing a luteinizing hormone (LH) surge is a major concern in controlled ovarian stimulation (COS). Several strategies have been developed over the years, including protocols with Gonadotrophin Releasing Hormone agonists and antagonists. More recently Progestin Primmed Ovarian Stimulation (PPOS) has shown to be equally effective in pituitary suppression, with comparable clinical and laboratorial outcomes. This is the case of a 34 year old female, with a previous diagnosis of primary infertility due to tubal factor and high ovarian reserve markers. The initial plan was to perform IVF/ICSI. followed by fresh blastocyst transfer. The chosen COS strategy was to use Alfacorifolitropin 150mg (Elonva®) and Cetrorelix acetate 0,25mg (Cetrotide®) in a flexible pituitary suppression protocol. However, because of elevated risk for Ovarian Hyper-stimulation Syndrome (OHSS) detected during ultrasound and hormonal monitoring, in order to diminish financial burden and to have a more patient friendly protocol, we switched cetrorelix acetate to oral dydrogesterone. COS was successful and resulted in 24 retrieved oocytes (16 metaphase 2 oocytes) without any premature LH peak. No OHSS symptoms occurred. Our main goal with this case report is to reinforce the feasibility and efficacy of this innovative approach, especially in patients aiming for a fresh embryo transfer, who present alert sings of OHSS during the stimulation. Developing friendlier and cheaper protocols in assisted reproduction makes the treatment more accessible and affordable.