Figure 5.

Cluster-wise results of pit frequency and chi-square tests. The colors in the clusters on the surface (left) indicating changes of pit frequency among fetal subgroups and examples of changes of frequency in six clusters are provided (right). Cluster indices and names correspond to those of Figure 1. Colors of the clusters represent the statistics of frequency change. Red: pit frequency in G_early over 0.3 and no significant change between subgroups. Light blue: significant increase of pit presence using chi-square test from G_early to G_mid. Purple: both high frequency in G_early (>0.3) and significant increase of pit presence using chi-square test from G_early to G_mid. Green: significant increase of pit presence using chi-square test from G_mid to G_late. Yellow: significant increase of pit presence using chi-square test from G_early to G_mid and from G_mid to G_late. Gray: low frequency in G_early (<0.3) and no significant change. ^*: significant change of pit presence (FDR corrected P < 0.05) between two subgroups.