單獨第2或第3天胚胎評估即可準確預估胚胎之品質

單獨第2或第3天胚胎評估即可準確預估胚胎之品質

第1天胚胎評估之準確性最低，
第2天胚葉細胞數目準確性>胚葉細胞大小一致性準確性>胚胎細胞碎片準確性

http://humrep.oxfordjournals.org/content/24/9/2104.full

Is there an advantage in scoring early embryos on more than one day?

1. Catherine Racowsky1,5, 
2. Lucila Ohno-Machado2,3, 
3. Jihoon Kim2 and
4. John D. Biggers4

+Author Affiliations

1. ¹Department of Obstetrics, Gynecology and Reproductive Biology, Brigham and Women's Hospital, Harvard Medical School, 75 Francis Street, ASB 1+3, Rm 082, Boston, MA 02115, USA
2. ²Decision Systems Group, Brigham and Women's Hospital, Harvard Medical School, Boston, MA 02115, USA
3. ³Division of Biomedical Informatics, Department of Medicine, University of California, San Diego, La Jolla, CA 92093, USA
4. ⁴Department of Cell Biology, Harvard Medical School, Boston, MA 02115, USA

1. 5Correspondence address. Tel: +1-617-732-5455; Fax: +1-617-975-0825; E-mail:cracowsky@partners.org

• Received November 25, 2008.
• Revision received April 30, 2009.
• Accepted May 6, 2009.

 

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Abstract

BACKGROUND This study was undertaken to determine what characteristics should be recorded on which days to build a predictive model for selection of Day 3 embryos.

METHODS Embryos failing to form a clinical sac or that formed a viable fetus (to ≥12 weeks), and transferred singly (n = 269) or in pairs (n = 1326) were scored for early cleavage and pronuclear status on Day 1, and cell number, fragmentation, and symmetry on Days 2 and 3, with number of nuclei per blastomere also recorded on Day 2. Seven candidate models were identified using a priori clinical knowledge and univariate analyses. Each model was fit on a training-set and evaluated on a test-set with resampling, with discrimination assessed using the area under the ROC curve (AUC) and calibration assessed using the Hosmer–Lemeshow statistics.

RESULTS Models built using Day 1, 2 or 3 scores independently on the 30 resampled data sets showed that Day 1 evaluations provided the poorest predictive value (median AUC = 0.683 versus 0.729 and 0.725, for Day 2 and 3). Combining information from Day 1, 2 and 3 marginally improved discrimination (median AUC = 0.737). Using the final Day 3 model fitted on the whole dataset, the median AUC was 0.732 (95% CI, 0.700–0.764), and 68.6% of embryos would be correctly classified with a cutoff probability equal to 0.3.

CONCLUSIONS Day 2 or Day 3 evaluations alone are sufficient for morphological selection of cleavage stage embryos. The derived regression coefficients can be used prospectively in an algorithm to rank embryos for selection.

Figure 1

8-Cell human embryos on Day 3 of culture with varying degrees of fragmentation and asymmetry, as reflected by the numerical scores on the images corresponding to the cell number, fragmentation score and asymmetry scores, respectively, as defined in Table I.

The arrows in (D) point to examples of fragmentation; bar = 25 µm.

Table I

List of embryonic features included in the study

Day	Feature	Comments (including coding of nominal data)
1	Time of evaluation	17.8–29 h after fertilization (target 25 h)
1	No. cells	Range: 1–6
1	Pronuclei	Code (day1stage): 0 = 1cell + 2PN; 1 = 1cell + 0PN; 2 = 2 cells; 3 = >2 cells
2	Time of evaluation	37.6–50.7 h (target = 44 h)
2	No. cells	Range: 1–11
2	Fragmentation*	Code: 0 = 0%; 1 = 1–9%; 2 = 10–25%; 3 = 26–50%; 4 = >50%
2	Symmetry	Code: 1 = No asymmetry; 2 = Moderate asymmetry; 3 = Severe asymmetry
2	Distribution of nuclei	Code: 0 = one or more blastomeres without a single nuclei; 1 = all blastomeres with a single nucleus
3	Time of evaluation	60.2–77.7 h (target = 68 h)
3	No. cells	Range: 1–14
3	Fragmentation*	Code: 0 = 0%; 1 = 1–9%; 2 = 10–25%; 3 = 26–50%; 4 = >50%
3	Symmetry	Code: 1 = No asymmetry; 2 = Some asymmetry; 3 = Severe asymmetry

• *Due to small numbers in groups having scores of three and four, these groups were combined with those having a score of two.