Can high levels of D-chiro-inositol in follicular fluid exert detrimental effects on blastocyst quality?

OBJECTIVE: It was previously shown that higher concentrations of myo-inositol in human follicular fluid improve oocyte and embryo quality, whereas D-chiro-inositol seems to worsen oocyte quality and ovarian response in polycystic ovary syndrome patients. Our study was the first one aiming to test whether different myo-inositol and D-chiro-inositol concentration in follicular fluids correlate with blastocyst quality in healthy young women. PATIENTS AND METHODS: Eight egg donors and eleven couples undergoing in vitro fertilization, were involved in a prospective observational study. Myo-inositol/D-chiro-inositol ratio was calculated in the follicular fluids and associated with different blastocyst grades. Donors were homogeneous and followed the same standard stimulation protocol. RESULTS: The ratio between myo-inositol and D-chiro-inositol was significantly higher in the specimens rated as good quality blastocysts, compared to those rated as poor-quality blastocysts. In this study, almost all the transferred blastocysts were graded as good quality and were correlated to lower D-chiro-inositol content in the follicular fluid; the implantation rate and pregnancy rate were satisfying. Our data suggest that the reduction of such ratio in follicular fluid seems to play a negative role in follicular development. CONCLUSIONS: We found a correlation between myo-inositol/D-chiro-inositol ratio in follicular fluid and blastocyst quality. The value of this ratio may represent a new biomarker for estimating the good features of blastocysts, and a prognostic factor of embryo implantation and pregnancy success. Moreover, the pre-treatment with myo-inositol in women undergoing in vitro fertilization (IVF) may improve oocyte quality and ART outcome. CLINICAL TRIAL REGISTRATION NUMBER: NCT03055442 (ClinicalTrials.gov registry).

Open versus closed vitrification of blastocysts from an oocyte-donation programme: a prospective randomized study.

The use of open carriers for embryo vitrification has raised safety concerns and therefore vitrification in closed systems has been proposed. However, the drop in the cooling rate emerges as a major drawback. The objective of the present study was to compare the efficiency of vitrification in open versus closed conditions. Blastocysts were randomly allocated either to open ultra-rapid vitrification (group I) or closed aseptic vitrification (group II). In group I, blastocysts were exposed to two solutions of ethylene glycol/dimethylsulphoxide (10%/10% and 20%/20%), while in group II, blastocysts were pretreated with a solution of lower concentration (5%/5%). A total of 208 and 224 vitrification-warming cycles were performed for groups I and II, respectively. Both groups were equal in terms of maternal age, sperm parameters and number and quality of blastocysts vitrified, warmed and transferred per cycle. Importantly, there was no significant difference between the groups in the analysed outcomes; embryo survival rate (84.1% versus 82.1%), clinical pregnancy rate (45.9% versus 42.4%), implantation rate (25.6% versus 24.5%), cycle cancellation rate (6.7% versus 8.5%) and live birth rate (41.2% versus 41.0%). These data suggest that ultra-rapid vitrification may be replaced by aseptic vitrification without affecting clinical efficiency.