Can Blastocyst Morphometrics Be a Non-invasive Predictive Marker for Clinical Pregnancy in In vitro Fertilisation...

Blastocyst diameter is a key morphometric indicator used to predict implantation. Some studies suggest, well-expanded blastocysts generally demonstrate significantly higher clinical pregnancy and live birth rates compared to smaller embryos.

The aim of this study was to investigate the predictive efficacy of morphometric parameters of a blastocyst on clinical pregnancy in in vitro fertilisation (IVF) cycles.

This was a prospective cohort study conducted at a tertiary care academic institution, involving 84 IVF/intracytoplasmic sperm injection cycles with a single blastocyst transfer in the fresh IVF cycle.

All the blastocysts were assessed using a calibrated annotation tool in Embryo viewer (EmbryoScope, Vitrolife, Sweden) to measure specific variables, such as maximum blastocyst width and area of each blastocyst at 118-120 h post-insemination, just before embryo transfer.

Continuous variables were compared using independent t-test or Mann Whitney U-test. For three -group comparisons, analysis of variance or the Kruskal-Wallis test was applied.

Among the women who had a clinical pregnancy, the mean width of the transferred blastocyst was significantly (P < 0.0001) larger (182.96 μm) than in those who did not conceive (144.09 μm). The empirical optimal cut-off of blastocyst diameter, which will lead to clinical pregnancy, was found to be 159.5 μm with a sensitivity of 92% and specificity of 85%. Significantly (P < 0.0001) larger blastocyst area 26,239 μm² (95% confidence interval [CI]: 24,686-27,792 μm²) was also seen among women with clinical pregnancy versus women without clinical pregnancy, 16,381 μm² (95% CI: 15,091-17671 μm²). The empirical optimal cut-off of blast area was found to be 20,134 μm² with a sensitivity of 90% and a specificity of 85%. The receiver operating characteristic curve was plotted for blastocyst diameter and blastocyst area, and the area under the curve for blastocyst diameter and blastocyst area was 0.934 and 0.930, respectively.

Objective morphometric evaluation of blastocyst width and area provides a simple, non-invasive and reliable predictor of clinical pregnancy in IVF cycles.