Table 1. A Large Study by Cahill et al (2012) Showing That 91% of Acidemic Babies Displayed Moderate Variability During the 30 Min Before Delivery [12].
| FHR pattern | pH ≤ 7.10 (57 newborns) | pH > 7.10 (5,331 newborns) | P value |
|---|---|---|---|
| Moderate baseline variability | 91.2% | 87.2% | - |
| Minimal baseline variability | 8.8% | 12.5% | 0.41 |
| Baseline tachycardia | 12.3% | 4.5% | - |
| Repetitive late decelerations | 15.8% | 7.3% | 0.05 |
| Repetitive variable decelerations | 49.1% | 32.5% | 0.03 |
| Early decelerations | None | None | - |
There were hardly any “early” decelerations in this large study, not because head compression does not cause decelerations, but very likely because of accident of (flawed) definitions. Late decelerations of duration < 60 s (i.e. descent time < 30 s) may have been wrongly classed as “variable”.