Study on the Influencing Factors and Correlation of Fetal Y Chromosome Concentration in NIPT Based on Ordered Clustering and Linear Regression

Abstract

To address the issue of individual differences affecting the accuracy of non-invasive prenatal testing (NIPT), especially the pain point of low free DNA concentration in the fetus of pregnant women with high BMI, this study analyzed the correlation between the concentration of the Y chromosome in the fetus and the gestational age and BMI of pregnant women. First, samples with abnormal GC content (not 40% to 60%) were excluded through data preprocessing. Then, histograms and scatter plots were drawn to initially observe the distribution and correlation characteristics of the variables. It was found that the scatter plot was difficult to visually determine the correlation. Subsequently, a grouped regression strategy was adopted: BMI was grouped by equal frequency, gestational weeks were determined based on the Jenks natural breakpoint method, combined with variance goodness-of-fit (GVF), pseudo-F statistics, Bayesian information criterion (BIC), and entropy weight method - TOPSIS method to determine the optimal 15 groups. After taking the mean of each group of variables, a univariate linear regression model was constructed, and the significance was verified through the F-test. The results showed that the concentration of the Y chromosome was significantly positively correlated with the gestational weeks (r= 0.6338, P=0.0112), and the degree of correlation was moderate. It was extremely significantly negatively correlated with BMI (r= -0.8658, P=0.0054), and the degree of correlation was relatively strong. This study provides data support for optimizing the timing of NIPT detection and improving the accuracy of detection in pregnant women with high BMI.