Main results
Arterial umbilical cord pH was significantly different between groups and the use of EA was a significant predictor for alterations in arterial umbilical cord pH in the propensity score adjusted linear regression model (7.25 ± 0.09 in no EA vs. 7.24±0.08 in the EA group (effect size -0.0057; 97.5% CI -0.0066 to -0.0047;P <0.001)). EA was associated with a less negative BE compared to no EA use (-5.89 ± 3.2 mmol/l compared to ‑6.15 ± 3.23 mmol/l (effect size 0.36; 97.5% CI 0.32 to 0.40;P <0.001)). In 23.5% of deliveries, BE was missing, while pH values were absent in 3.7%. Both linear regression model results were similar when additionally adjusting for morbidity (see Table 3).
APGAR scores after 1, 5, and 10 minutes were similar between groups. An AS5<7 was more likely in neonates of mothers with EA (1.0% compared to 0.6%; OR 1.45; 95% CI 1.29 to 1.63;P <0.001). The postpartum admission rate of neonates to a NICU or paediatric ward was significantly higher in the EA group (4.7% versus 3.4%) with an estimated OR for EA of 1.39 (95% CI 1.33 to 1.46; P <0.001). EA was not significantly associated with increased perinatal mortality (OR 1.33; 95% CI 0.79 to 2.25;P =0.288).