A quantitative approach to blastocyst quality evaluation: morphometric analysis and related IVF outcomes

To quantify blastocyst morphologic parameters with a feasible and standardized tool, investigating their predictive value on implantation outcome.

The study retrospectively analyzes 124 blastocysts from 75 patients. Quantitative measurements of blastocyst expansion, inner cell mass and trophoectoderm were taken using digital image analysis software.

Blastocysts areas were found to be ranging from 11626.2 up to 35076.4 μm(2). The area of an early blastocyst is A ≤ 18500 μm(2) with a mean diameter d = 140 ± 9 μm, and the area of an expanded blastocyst is A ≥ 24000 with d = 190 ± 9 μm. While blastocyst mean area was not related to implantation rate, more expanded blastocysts displayed a significantly higher implantation rate. Trophoectoderm cell number is a predictor of positive outcome: since a higher of cells (25.6 ± 11.3 vs 16.3 ± 12.8) `forming a tightly knit epithelium is prognostic of implantation potential. Conversely, inner cell mass size is significantly related to implantation only in expanded blastocysts (3122.7 ± 739.0 vs. 2978.1 ± 366.0 μm(2)).

Evaluation of blastocyst morphology with a digital image system could be a valuable tool to standardize blastocyst grading based on quantitative parameters. Therefore, digital analysis may be helpful in identifying the best blastocyst to transfer.