Day-2胚胎等級最重要指標依次為: (1) 胚葉數目; (2) 胚葉大小一致性; (3) 胚葉單細胞核

5項指標評估Day-2胚胎等級
 blastomere number (BL), 胚葉數目
fragmentation, 碎片雜質
blastomere size variation (‘equality’, EQ), 胚葉大小一致性
symmetry of the cleavage 分裂速度
mononuclearity in the blastomeres (NU). 胚葉單細胞核


其中最重要的指標依次為: (1) 胚葉數目; (2) 胚葉大小一致性; (3) 胚葉單細胞核
http://humrep.oxfordjournals.org/content/22/2/548.full

Construction of an evidence-based integrated morphology cleavage embryo score for implantation potential of embryos scored and transferred on day 2 after oocyte retrieval

1. J. Holte¹,⁴, 
2. L. Berglund², 
3. K. Milton¹, 
4. C. Garello³, 
5. G. Gennarelli³, 
6. A. Revelli³and 
7. T. Bergh¹

+Author Affiliations

1. ¹Carl von Linné Clinic
2. ²Uppsala Clinical Research Center, Uppsala University, Uppsala Science Park, Uppsala, Sweden and
3. ³Department of Gynaecological and Obstetrical Sciences, University of Turin, Turin, Italy

1. 4To whom correspondence should be addressed at: Carl von Linné Clinic, Uppsala Science Park, S-751 83 Uppsala, Sweden. E-mail: jan.holte@linne.se

• Received February 27, 2006.
• Revision received September 6, 2006.
• Accepted September 12, 2006.

 

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Abstract

BACKGROUND: Evidence-based morphological embryo scoring models for ranking of implantation potential are still scarce, and the need for a precise model increases when aiming for singleton pregnancies. METHODS: Prospectively, 2266 IVF/ICSI double-embryo, day 2 transfers were studied. The five variables scored in 3- to 5-step scales for the embryos transferred are blastomere number (BL), fragmentation, blastomere size variation (‘equality’, EQ), symmetry of the cleavage and mononuclearity in the blastomeres (NU). The scoring results of embryos with an individual traceability from scoring to implantation, i.e. treatments resulting in either no implantation (n = 1385) or twin implantation (n = 228), were studied for prognostic potential. RESULTS: Although all five variables correlated highly with implantation potential, only BL, NU and EQ remained independently significant after regression analysis. The equation thus derived formed the basis for a 10-point integrated morphology cleavage (IMC) embryo score. A table with the scoring point for each possible combination of the embryo variables is presented. The scoring model was statistically validated on the singleton pregnancy group (n = 653). CONCLUSIONS: We suggest that this IMC embryo scoring, incorporating cleavage stage and information on the variation in blastomere size and the number of mononucleated blastomeres, may optimize embryo ranking and selection for day 2 transfers.

Figure 1.

Embryo variables. Number of blastomeres (BL: 2, 3, 4, 5 or ≥6 blastomeres). Degree of fragmentation (FR): 0, no; 1, ≤10%; 2, >10 ≤ 25%; 3, >25 ≤ 50% and 4, >50% fragmentation. Variation of sizes of the blastomeres (‘Equality’, EQ): 0 = uniform size of the blastomeres, 1 = varying size but <50% variation and 2 = more than 50% variation in blastomere size. Symmetry of the cleavage (‘Symmetry’, SY): 0 = full symmetry of the cleaved embryo, 1 = slightly asymmetric cleavage and 2 = pronounced asymmetry. The parameter ‘Nucleus score’ (NU) was defined as the number of visible mononucleated blastomeres divided by the total number of blastomeres in the embryo (to correct for cleavage rate); Nucleus score 0 = a ratio of 0–0.25; Nucleus score 1 = ratio >0.25–0.50; Nucleus score 2 = ratio >0.50–0.75 and Nucleus score 3 = ratio >0.75. Nucleus score –1 denotes that the embryo contains at least one multinucleated blastomere.