Embryo scoring as a prognostic tool in IVF treatment

TLDR

The study defines a semi‑quantitative, non‑invasive embryo scoring method to select embryos before transfer and prognostically evaluate IVF outcomes. Embryos were graded under an inverted microscope by assessing the quantity of anucleate fragments released during early cleavage and their developmental speed. High embryo scores were associated with higher pregnancy and multiple pregnancy rates, but showed no difference among ongoing, aborted, or chemical pregnancies; in double and triple transfers, higher scores correlated with higher implantation rates, enabling the derivation of five criteria that predict high risk of multiple pregnancy and suggest limiting transfers to two embryos when those criteria are met.

Abstract

A semi-quantitative and non-invasive method for scoring embryos obtained after in-vitro fertilization (IVF) has been defined, aiming at selection of embryos before transfer and at prognostic evaluation of IVF trials. Grading of embryos observed on the inverted microscope was essentially based on the amount of anucleate fragments expelled during early cleavage and on developmental speed. Embryos endowed with a high score were more often associated with pregnancy and in particular with the occurrence of multiple pregnancy. No difference was observed between scores attributed to embryos related to ongoing, aborted or chemical pregnancies. Average embryonic scores corresponding to double and triple transfers differed significantly in failures as well as pregnancies. The better quality of embryos replaced in triple transfers was also apparent from the significantly higher implantation rate per embryo observed in this group. From our results, five criteria including clinical data and embryonic scores can be derived for defining a high risk of multiple pregnancy prior to transfer. It might be warranted to replace only two embryos when these conditions are fulfilled.