Correlations between collagen concentrations with gestational age eliminated
| Variable | PIIINP | PICP | ICTP | PICP/ICTP |
| PIIINP | 1 | |||
| PICP | 0.650 | 1 | ||
| ICTP | 0.282 | 0.346 | 1 | |
| PICP/ICTP | 0.350 | 0.634 | −0.479 | 1 |
PIIINP, collagen type III N-terminal propeptide; PICP, collagen type I C-terminal propeptide; ICTP, C-terminal cross linked telopeptide.