Related Experiment Video
Updated: Jul 6, 2025
Fertility Preservation Through Oocyte Vitrification: Clinical and Laboratory Perspectives
Published on: September 16, 2021
Should the trigger to oocyte retrieval interval be different in progestin-primed ovarian stimulation cycles?
Baris Ata1, Aysu Cakar2, Engin Türkgeldi3
1Department of Obstetrics and Gynecology, Koc University School of Medicine, Istanbul, Turkey; ART Fertility Clinics, Dubai, United Arab Emirates; Assisted Reproduction Unit, Koc University Hospital, Istanbul, Turkey.
Research Question:
Does the trigger to oocyte retrieval interval (TORI) affect oocyte maturation rates differently in progestin-primed ovarian stimulation (PPOS) and gonadotrophin-releasing hormone (GnRH) antagonist cycles?
Design:
This was a retrospective cohort study. The interaction between the stimulation protocol and TORI was assessed in a linear mixed effects multivariable regression analysis with oocyte maturation rate as the dependent variable, and stimulation protocol (GnRH antagonist or PPOS), age (continuous), gonadotrophin type (FSH or human menopausal gonadotrophin), trigger (human chorionic gonadotrophin [HCG] or GnRH agonist), TORI (continuous) and days of stimulation (continuous) as the independent variables. Oocyte maturation rate was defined as number of metaphase II oocytes/number of cumulus-oocyte complexes retrieved. The maturation rate was calculated per cycle and treated as a continuous variable.
Results:
A total of 473 GnRH antagonist and 205 PPOS cycles (121 conventional PPOS and 84 flexible PPOS) were analysed. The median (quartiles) female age was 36 (32-40) years. Of these cycles, 493 were triggered with HCG and 185 with a GnRH agonist. The TORI ranged between 33.6 and 39.1 h, with a median (quartiles) of 36.2 (36-36.4) hours. Maturation rates were similar between fixed PPOS, flexible PPOS and antagonist cycles (median 80%, 75% and 75%, respectively, P = 0.15). There was no significant interaction between the stimulation protocols and TORI for oocyte maturation.
Conclusions:
PPOS cycles do not seem to require a longer TORI than GnRH antagonist cycles.
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