Dr. Junjia Huang. New Trends in the European Society of Human Reproduction and Embryology (ESHRE) in Rome 2010

Due to the religious belief, many Europeans state fertilization marks the beginning of human life, it's impossible to perform fetal reduction surgery. An extreme example for this scenario is Italy, where Italian government restricted IVF insemination of a maximum of three eggs at a time for any one IVF patient. In addition, compared with assisted reproductive technology (ART), multiple-birth consume significantly more economic burdens in the welfare states, and the partial, or even total, insurance coverage for ART leads to strict restrictions on the number of embryos implanted, even toward the policy of single embryo transfer.

Morphological assessment is the only reference of embryo quality for selection previously; more and more studies have shown that normal morphology not necessarily warrantnormal chromosome content, so conventional morphological evaluation is insufficient for embryo selection, instead, more precise biomarkers may serve a better strategy for single embryo selection.

According to the purposes, embryo selection methodology can be divided into invasive and non-invasive methods. Invasive embryo selection in based on the technology of embryo biopsy and can be further categorized into genomic and transcriptomic levels; non-invasive methods is mainly based on the analysis of embryo culture medium and can be classified into proteomic and metabolomics levels.

Genomic analysis is the genetic testing of first polar body, 8-cell, or blastocyst for chromosomal abnormality, aneuploidy, or SNP genotyping of genetic variation; Gene expression analysis id carried out via RT-PCR, amplification of mRNA or cDNA chips; for example, IGF-1 and IL-1 expression is known to be associated with embryo activity. Transcriptomic profiling can be performed tailored to particular panel of gene expression, such as regulation of adhesion and apoptosis (BCL2), etc.

Proteomic and metabolomics assessments are the analysis of proteins and metabolites in the conditioned embryo culture medium. Proteomic analysis is limited by the fact that the amount of protein secretion is very scarce in the embryo, the characteristics of protein that it cannot be amplified as DNA, and the dynamic pattern of protein expression. Metabolomic profiling can focus on the uptake of culture media substances providing energy, such as glucose and pyruvate; or the production of metabolites such as lactate and ammonium; as well as the uptake and production of amino acids. The correlation with embryonic viability can be carried out by NIR analysis. There are more and more studies and clinical data reported recently that analysis of embryonic metabolites is an important indicator of embryo viability, with the combination of morphological evaluation, it appears to be possible to select the best embryo for implantation from embryos with equally good morphology.