Figure 4

PCA-LDA scores plot of ATR-FTIR spectra with regards to LD1: Healthy Cervix vs. Cone Depth (a) together with absorbance per wavenumber (b). Mean/SD (a) for each group was: 0.22/0.07 for healthy cervix; 0.15/0.07 for <10 mm; 0.19/0.07 for 10–14 mm; 0.13/0.04 for ≥15 mm. A significant difference along LD1 was detected for healthy cervix vs. <10 mm (p = 0.0008; 95 CI = 0.03 to 0.12); and for healthy cervix vs. ≥15 mm (p = 0.001; 95 CI = 0.03 to 0.15). No significant difference along LD1 was detected for healthy cervix vs. 10–14 mm (p = 0.13; 95 CI = −0.01 to 0.08). Absorbance associated with Amide II was shown to have a significant positive rate of change for <10 mm group compared with healthy cervix, indicating higher bioavailability (b). Similarly, absorbance associated with Amide I and II were shown to have a significant positive rate of change for ≥15 mm compared with healthy cervix, whilst absorbance associated with DNA was shown to have a negative rate of change, indicating lower bioavailability. ATR-FTIR: Attenuated total reflection Fourier-transform Infrared; CI: Confidence interval; LD1: Linear Discriminant 1; PCA-LDA: Principal Component Analysis coupled to Linear Discriminant Analysis; SD: Standard deviation.