باروری و ناباروری ایران

STUDY QUESTION: Are the mean numbers of blastocysts obtained from sibling cohorts of oocytes recruited after follicular phase and

luteal phase stimulations (FPS and LPS) in the same ovarian cycle similar?

SUMMARY ANSWER: The cohorts of oocytes obtained after LPS are larger than their paired-FPS-derived cohorts and show a comparable

competence, thus resulting in a larger mean number of blastocysts.

WHAT IS KNOWN ALREADY: Three theories of follicle recruitment have been postulated to date: (i) the ‘continuous recruitment’ theory,

(ii) the ‘single recruitment episode’ theory and (iii) the ‘wave’ theory. Yet, a clear characterization of this crucial biological process for

human reproduction is missing. Recent advances implemented in in vitro fertilization (IVF), such as blastocyst culture, aneuploidy testing and

vitrification, have encouraged clinicians to maximize the exploitation of the ovarian reserve through tailored stimulation protocols, which is

crucial especially for poor prognosis patients aiming to conceive after IVF. LPS has been already successfully adopted to treat poor prognosis

or oncological patients through Duostim, LPS-only or random-start ovarian stimulation approaches. Nevertheless, little, and mainly retrospective,

evidence has been produced to support the safety of LPS in general. Feasibility of the LPS approach would severely question the classic

‘single recruitment episode’ theory of follicular development.

STUDY DESIGN, SIZE, DURATION: This case-control study was conducted with paired follicular phase- and luteal phase-derived

cohorts of oocytes collected after stimulations in the same ovarian cycle (DuoStim) at two private IVF clinics between October 2015 and

December 2017.