Influence of combined oral contraceptive pill before PPOS protocol on egg donors and recipients’ outcomes: an international multicenter retrospective study

Purpose: This study aims to evaluate whether using a combined oral contraceptive pill (COCP) pre-treatment before controlled ovarian hyperstimulation (COH) may negatively influence ovarian response in donors and treatments outcomes in recipients when a progestin-primed ovarian stimulation (PPOS) protocol is used in oocyte donation treatments. Methods: Multicenter retrospective cohort study evaluating outcomes of 397 COH cycles in oocyte donors, with and without COCP pre-treatment. The retrieved oocytes were used for 216 oocyte donation cycles in recipients. Results: In donors, the No-COCP group obtained a higher number of total, MII, and useful oocytes, similar stimulation days, total FSH dose used, and cancellation rate due to low response, while the COCP group showed significantly higher cancellations for low LH levels, indicative of long-lasting pituitary suppression COCP related. In recipients, both groups showed similar fertilization rate and blastocyst formation rate. Miscarriage rate (MR) was significantly higher in the COCP group, while higher implantation rate, ongoing pregnancy rate (OPR), and live birth rate (LBR) were obtained in the No-COCP group. Conclusions: Donor response to COH with PPOS protocol appears to be negatively influenced by COCP pre-treatment, with implications for oocyte donation treatment outcomes in recipients, including higher MR and lower OPR/LBR. Further studies are needed to confirm these findings.