Controlled Ovarian Stimulation Initiated at Different Phases of the Menstrual Cycle for Fertility Preservation in Oncological Patients: a Retrospective Study.

The purpose of this study is to compare conventional start in early follicular phase (EFP) with late follicular phase (LFP) and luteal phase (LP) in controlled ovarian stimulation (COS) for fertility preservation (FP) to assess differences in clinical outcomes. Retrospective study of the first cycles of COS for FP in oncological patients between 2012 and 2020 in a tertiary hospital. Two-hundred forty-eight cycles were classified into 3 groups: 176 cycles in EFP, 8 cycles in LFP, and 52 cycles in LP.