Table 3.
The quantile regression analysis for fetal ductus venosus Doppler velocity indices
| Dependent variable | Percentile regression | CRL parameter estimates | |
|---|---|---|---|
|
| |||
| Coefficient (SE) [95% CI] | P | ||
| DVPI | 5th | 4.228E-18 (0.0035) [−0.007–0.007] | 1.000 |
| Median | 0.002 (0.0013) [−0.001–0.005] | 0.132 | |
| 95th | 0.003 (0.0039) [−0.005–0.011] | 0.422 | |
| DVRI | 5th | −0.004 (0.0018) [−0.008–−0.001] | 0.018* |
| Median | −3.128E-18 (0.0007) [−0.001–0.001] | 1.000 | |
| 95th | −0.001 (0.0006) [−0.002–0.000] | 0.030* | |
| DV S/A ratio | 5th | 0.002 (0.0098) [−0.017–0.022] | 0.805 |
| Median | 0.001 (0.0104) [−0.019–0.021] | 0.916 | |
| 95th | 0.012 (0.0552) [−0.096–0.120] | 0.827 | |
*Significant P-value for the estimated coefficient of the independent variable (CRL in mm). CI=Confidence interval; DV=Ductus venosus; DVPI=DV pulsatility index; DVRI=DV resistance index; SE=Standard error; CRL=Crown-rump length; S/A=S-wave maximum velocity/A-wave minimum velocity