Expert Opinion on Refined and Extended Key Performance Indicators for Individualized Ovarian Stimulation for ART.

Objective: To assess the adequate ovarian follicular development and oocyte recovery between ovarian potential (antral follicle count [AFC]) before the start of ovarian stimulation (OS) and oocyte quantity and quality at oocyte retrieval. A holistic overview of the current key performance indicators (KPIs) was applied to identify the complementary strengths and identify where the current repertoire can be expanded.

Design: Expert opinion.

Subjects: Not applicable.

Intervention: None.

Main outcome measures: To formulate a proposal for a refined and expanded repertoire of KPIs for individualized OS for Assisted Reproductive Technology.

Results: The performance and outcomes of OS on ovarian follicular development can be evaluated through the application of defined KPIs. Current KPIs for OS are the ovarian sensitivity index (OSI), the follicular output rate (FORT), the oocyte retrieval rate (ORR), and the follicle to oocyte index (FOI). Notably, there are no specific KPIs dedicated to the assessment of follicular development (i.e., recruitment, selection, growth and dominance). In light of this, we recommend expanding the current KPIs for OS to include "Early FORT" (accounting for the number of follicles measuring ≥10-11 mm on Day 5/6 of OS relative to AFC) and "Modified FORT" (the ratio between the number of follicles measuring ≥12 mm at the time of oocyte maturation triggering and AFC); the extension of ORR to include two discrete categories at oocyte retrieval: follicles ≥12 mm and follicles ≥16 mm, to ensure all responsive follicles are accounted for; and FOI to be measured at oocyte maturation triggering and oocyte retrieval ("Advanced FOI").

Conclusions: Once validated and adopted in clinical practice, we envisage that the proposed expanded KPIs measuring the effect of OS on follicular development (recruitment, selection, growth and dominance) will increase the understanding of the relationship between ovarian reserve measured by AFC and oocyte quantity and quality at oocyte retrieval. This understanding will enable physicians to better evaluate the direct effect of different gonadotropins and doses on ovarian response, leading to a more personalized approach to OS in the context of ART treatment.