Morphological analysis at compacting stage is a valuable prognostic tool for ICSI patients.

In terms of treatment outcome, little prognostic power is attributed to day-4 morphology. A day-4 score was applied to 56 patients separating non-compacting embryos from compacting (some areas of compaction) and fully compacted embryos. The latter were further subdivided according to the morphology of compaction. Grade C1 embryos represented optimal quality, while grades C2 (exclusion of fragments) and C3 (exclusion of blastomeres) were characterized by a loss of cytoplasm. Grade 4 embryos (C4) showed incomplete compaction with several blastomeres not yet incorporated into cell mass. Pooled embryos without compaction showed a reduced (P < 0.001) blastulation (28.8%) as compared with compacting embryos with the same cell number (68.8%), which, in turn, revealed lower (P < 0.05) rates of blastulation as compared with concepti that completed compaction process (84.6%). Among fully compacted embryos grade C1 had a better (P < 0.01) blastocyst formation rate (94.4%) as compared with grade C3 (68.2%). Grade C1 embryos showed significantly higher rates of top-quality blastocysts as compared with grade C2 (P < 0.05) and C3 (P < 0.01). Blastocysts deriving from grade C1/C4 embryos led to a higher pregnancy rate as compared with the C2/C3 counterparts (P < 0.05). This modified score allows for adequate prediction of both blastocyst formation/quality and pregnancy.

Presence, but not type or degree of extension, of a cytoplasmic halo has a significant influence on preimplantation development and implantation behaviour.

BACKGROUND: Since there is considerable disagreement in grading cytoplasmic haloes, this prospective study was set up to evaluate if certain subtypes of haloes are related to further development. METHODS: Out of a total of 152 patients, 713 zygotes could be checked for the formation of a halo. Where present, haloes were subdivided into concentric (symmetric) and polar (asymmetric) types. In addition, each halo was measured accurately to see if the extension of the halo might influence further development. In parallel, pronuclear patterns were checked. RESULTS: Halo-positive zygotes did not differ from halo-negative ones in terms of embryo quality and blastocyst formation rate. However, quality of blastocysts (assessed by their inner cell mass consistency) was significantly increased (P < 0.001) if a halo appeared at zygote stage. This phenomenon was not related to type of halo or degree of halo. In terms of pronuclear pattern, pattern 0 (0A, 0B) led to significantly more blastocysts (P < 0.001) of better quality (P = 0.002) compared with patterns 1-5. A stepwise logistic regression showed no relationship between different halo types and pronuclear pattern 0. CONCLUSIONS: The present study indicates that any halo has a positive prognostic value on blastocyst quality, irrespective of the fact that it is light or extreme, polar or concentric. In addition, the developmental advantage of pattern 0 is confirmed.