While the number of assisted reproduction cycles increases worldwide, the introduction of actual technological improvements in the ability to quickly and non-invasively identify the best embryos for transfer still represents a critical goal for reproductive medicine. Indeed, embryo assessment is currently performed through the analysis of morphology and cleavage rate. Recent studies have sought to identify a correlation between qualitative-quantitative profiles of small molecules of metabolic interest and the outcome of embryo transfer. Some of these molecules seem to be best suited for this purpose, including glucose, lactate, pyruvate or amino acid levels. Approaches relying on both optical and non-optical spectroscopy have been proposed to non-invasively monitor the embryo culture media. However, the non-invasive approach only offers an indirect strategy to monitor embryos and a turn-around solution to bypass the limits of detection of these analytical techniques. In this paper the investigators pave the way for direct assessment of embryos through the mass spectrometry-based analysis of blastocoele fluid, which is withdrawn from the blastocoele cavity prior to cryostorage of blastocysts. The investigators show how it is possible to detect most of the already documented metabolites of interest right at the very heart of the blastocyst, without disrupting the workflow of a classic laboratory pipeline.

Inclusion Criteria:

• Ovarian hyperstimulation disease
• Blastocyst formation

All the patients that are unable to be subjected to embryo transfer due to her ovarian hyperstimulation. In those cases the embryos will be vitrified and during this procedure we collapse the blastocyst sucking the fluid.