Acidemia at birth in the vigorous infant as a trigger incident to assess intrapartum care with regard to CTG patterns.

Objective: To evaluate if acidemia in vigorous infants is a useful variable in the assessment of intrapartum care with regard to cardiotocographic (CTG) patterns during the second stage.

Methods: Cases (n = 241) were infants with an umbilical artery pH < 7.05, controls (n = 482) were infants with pH ≥ 7.05. Apgar score was ≥ 7 at 5 min in both groups. CTGs during the last two hours of labor were assessed and neonatal outcomes compared. A sub-analysis of cases with metabolic acidemia: pH < 7.00 and base deficit ≥ 12 mmol/L and acidemia: 7.00 < pH < 7.05 was performed.

Results: 63% of cases had a pathological CTG versus 26% of controls (p < 0.001). Patterns with severe variable decelerations had a significantly longer duration in cases. Metabolic acidemia was significantly associated with severe variable decelerations and decreased variability. Infants to cases were admitted to neonatal care in 19% versus 2% of controls (p < 0.001). With metabolic acidemia, 32% were admitted.

Conclusion: An umbilical artery pH < 7.05 at birth of vigorous infants may be a useful variable for quality control of intrapartum management with regard to the assessment of second-stage CTGs. Differences in duration of pathological patterns indicate passiveness in academic cases.