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Published on: September 5, 2011
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Working Towards a Reproducible Method for Quantifying Placental Syncytial Knots
Patricia K Senagore1, Claudia B Holzman1, W Tony Parks2,3
11 Department of Epidemiology and Biostatistics, Michigan State University College of Human Medicine, West Fee Hall, 909 Fee Road, Room B601, East Lansing, MI 48824, USA.
Summary
A new method for counting placental syncytial knots (SK) improves reliability in assessing pregnancy complications. This protocol aids in distinguishing normal from abnormal placental development, crucial for understanding pregnancy outcomes.
Area of Science:
- Reproductive Biology
- Pathology
- Perinatal Medicine
Background:
- Prominent syncytial knots (SK) in placentas are indicators of advanced gestation or placental malperfusion.
- Previous methods for quantifying SK lacked reproducibility and interrater reliability.
- Understanding SK requires reliable quantification to assess their impact on placental development and pregnancy outcomes.
Purpose of the Study:
- To develop a simple, reproducible protocol for counting syncytial knots (SK).
- To demonstrate interrater reliability for SK counting across different placental parameters.
- To establish a reliable method for categorizing SK counts as normal or abnormal.
Main Methods:
- Developed criteria for defining SK and a grid system for counting the percentage of villi with SK.
- Two pathologists assessed placental disc sections from 151 placentas across 8 defined groups.
- Evaluated interrater reliability using weighted kappa statistics and Spearman correlation coefficients.
Main Results:
- Achieved overall very good interrater agreement (kappa = 0.60) and high correlation (Spearman > 0.70).
- Highest agreement was observed for preterm placentas (kappa = 0.61) and SK associated with lesions (kappa = 0.67).
- Lower agreement was found in the absence of diffuse prominent SK (DPSK) (kappa = 0.22) or when DPSK was not associated with a lesion (kappa = 0.32).
Conclusions:
- The proposed protocol offers a reliable approach for quantifying syncytial knots (SK).
- This method can categorize SK counts as normal vs. abnormal or provide continuous measures.
- Further pretraining is recommended to enhance agreement, particularly for placentas with few SK or those without associated lesions.
