Elevated resting tonea N=567 Normal resting tone N=1643
P value
OR (95% CI)
aOR (95% CI)b
Composite neonatal morbidityc 29 (5.1) 48(2.9) 0.01 1.79 (1.16-2.87) 1.70 (1.06-2.74)
Hypoxic ischemic encephalopathy 1 (0.2) 1 (0.1) 0.43
Hypothermia treatment 2 (0.4) 3 (0.2) 0.46
Intubation 3 (0.5) 9 (0.6) 0.96
Seizures - 3 (0.2) 0.31
Neonatal death 1 (0.2) 1 (0.1) 0.43
Umbilical artery pH < 7.1 10 (1.8) 17 (1.0) 0.17
Oxygen therapy 15 (2.7) 30 (1.8) 0.23
NICU admissiond 9 (1.6) 14 (0.9) 0.14 1.88 (0.81-4.36) 1.79 (0.77-4.18)
5-minute Apgar score <7 16 (2.8) 26 (1.6) 0.06 1.81 (0.96-3.39) 1.73 (0.92-3.26)
Umbilical artery
pH <7.2 97 (17.1) 165 (10.2) <0.01 1.83 (1.39-2.40) 1.81 (1.38-2.37)
Lactate ≥ 4 mmol/l 178 (31.5) 382 (23.7) <0.01 1.48 (1.20-1.83) 1.45 (1.17-1.80)
aElevated tone defined as > 75th percentile bAdjusted for chorioamnionitis, amnioinfusion cComposite Neonatal Morbidity: Hypoxic Ischemic encephalopathy, hypothermia treatment, intubation, seizures, UA pH≤7.1, oxygen requirement, and neonatal death dNeonatal intensive care admission aElevated tone defined as > 75th percentile bAdjusted for chorioamnionitis, amnioinfusion cComposite Neonatal Morbidity: Hypoxic Ischemic encephalopathy, hypothermia treatment, intubation, seizures, UA pH≤7.1, oxygen requirement, and neonatal death dNeonatal intensive care admission aElevated tone defined as > 75th percentile bAdjusted for chorioamnionitis, amnioinfusion cComposite Neonatal Morbidity: Hypoxic Ischemic encephalopathy, hypothermia treatment, intubation, seizures, UA pH≤7.1, oxygen requirement, and neonatal death dNeonatal intensive care admission aElevated tone defined as > 75th percentile bAdjusted for chorioamnionitis, amnioinfusion cComposite Neonatal Morbidity: Hypoxic Ischemic encephalopathy, hypothermia treatment, intubation, seizures, UA pH≤7.1, oxygen requirement, and neonatal death dNeonatal intensive care admission aElevated tone defined as > 75th percentile bAdjusted for chorioamnionitis, amnioinfusion cComposite Neonatal Morbidity: Hypoxic Ischemic encephalopathy, hypothermia treatment, intubation, seizures, UA pH≤7.1, oxygen requirement, and neonatal death dNeonatal intensive care admission aElevated tone defined as > 75th percentile bAdjusted for chorioamnionitis, amnioinfusion cComposite Neonatal Morbidity: Hypoxic Ischemic encephalopathy, hypothermia treatment, intubation, seizures, UA pH≤7.1, oxygen requirement, and neonatal death dNeonatal intensive care admission