Table 3. Birthweight z-scores according to fetal flow tertiles in the reference and the pregestational diabetes mellitus population (160 and 49 participants, respectively).
| Flow tertiles | Birthweight z-scores | p-value† | ||||||
|---|---|---|---|---|---|---|---|---|
| Reference | Pregestational diabetes | |||||||
| N | mean | CI | n | mean | CI | |||
| Umbilical flow | lower | 191 | -0.32 | -0.45 –-0.18 | 66 | 0.62 | 0.23–1.02 | <0.0001 |
| middle | 192 | -0.04 | -0.18–0.09 | 41 | 1.24 | 0.75–1.74 | <0.0001 | |
| upper | 191 | 0.19 | 0.05–0.32 | 85 | 1.54 | 1.19–1.88 | <0.0001 | |
| p * | <0.001 | 0.003 | ||||||
| Umbilical flow to liver | lower | 185 | -0.24 | -0.38 –-0.10 | 40 | 0.27 | -0.21–0.74 | 0.007 |
| middle | 185 | -0.10 | -0.24–0.04 | 25 | 1.12 | 0.52–1.72 | <0.0001 | |
| upper | 185 | 0.17 | 0.03–0.31 | 58 | 1.79 | 1.40–2.18 | <0.0001 | |
| p * | <0.001 | <0.001 | ||||||
| Ductus venosus flow | lower | 181 | 0.18 | 0.04–0.32 | 62 | 1.28 | 0.86–1.70 | <0.0001 |
| middle | 181 | -0.12 | -0.26–0.23 | 25 | 0.85 | 0.19–1.51 | <0.0001 | |
| upper | 181 | -0.25 | -0.39 –-0.11 | 51 | 1.14 | 0.68–1.61 | <0.0001 | |
| p * | <0.001 | 0.548 | ||||||
| Ductus venosus fraction | lower | 178 | -0.07 | -0.22–0.07 | 62 | 1.47 | 1.06–1.88 | <0.0001 |
| middle | 178 | -0.01 | -0.15–0.14 | 28 | 1.05 | 0.44–1.66 | <0.0001 | |
| upper | 178 | -0.09 | -0.24–0.05 | 33 | 0.66 | 0.10–1.22 | 0.001 | |
| p * | 0.671 | 0.067 | ||||||
| Left portal vein blood velocity¥ | lower | 184 | -0.26 | -0.40 - -0.12 | 38 | 0.62 | 0.10–1.13 | <0.0001 |
| middle | 185 | 0.03 | -0.12–0.17 | 51 | 0.84 | 0.39–1.28 | <0.0001 | |
| upper | 184 | 0.07 | -0.07–0.22 | 113 | 1.44 | 1.14–1.74 | <0.0001 | |
| p * | 0.002 | 0.009 | ||||||
| Portal vein flow | lower | 186 | -0.41 | -0.55 - -0.27 | 35 | 1.45 | 0.89–2.00 | <0.0001 |
| middle | 186 | -0.01 | -0.14–0.14 | 19 | 0.77 | 0.02–1.53 | 0.003 | |
| upper | 186 | 0.20 | 0.07–0.34 | 40 | 1.26 | 0.74–1.78 | <0.0001 | |
| p * | <0.001 | 0.364 | ||||||
| Portal vein fraction | lower | 174 | -0.12 | -0.26–0.03 | 34 | 1.74 | 1.17–2.31 | <0.0001 |
| middle | 173 | -0.05 | -0.20–0.10 | 9 | 0.73 | -0.38–1.83 | 0.021 | |
| upper | 173 | -0.05 | -0.20–0.10 | 33 | 0.91 | 0.33–1.49 | <0.0001 | |
| p * | 0.761 | 0.085 | ||||||
| Total venous flow to liver | lower | 175 | -0.31 | -0.46 - -0.17 | 22 | 0.499 | -0.20–1.20 | 0.001 |
| middle | 175 | -0.05 | -0.19–0.09 | 17 | 1.380 | 0.58–2.18 | <0.0001 | |
| upper | 175 | 0.17 | 0.02–0.31 | 37 | 1.656 | 1.12–2.20 | <0.0001 | |
| p * | <0.001 | 0.037 | ||||||
Flow variables were divided into tertiles defined by the distribution in the reference population (upper, middle, lower), n; total number of observations
*Birthweight z-score difference between fetal blood flow tertiles tested by ANOVA within each population (table read vertically)
† Birthweight z-score difference between the reference and study populations in flow tertiles tested by independent sample T-test (table read horizontally); CI, confidence interval; Flow, volume blood flow (mL/min); z-score, standard deviation score
¥ Flow velocity, time-averaged maximum blood velocity (cm/sec).