The correlation between total deceleration and acceleration surface areas on electronic fetal monitoring and neonatal cord blood pH in postdate pregnancies.

OBJECTIVE: To assess the correlation between the total decelerations area in the final 120 min before delivery and neonatal cord blood pH in postdate pregnancies. METHODS: This cross-sectional study included women with gestational age greater than 41 weeks, singleton pregnancy, and a category II electronic fetal monitoring (EFM) of at least 30 min during the final 120 min before delivery. We included postdate deliveries of an otherwise low-risk parturient population. Each area was calculated as duration × depth × 1/2. Correlations were tested using the Spearman correlation coefficient. RESULTS: A total of 100 EFMs were included in the analysis. Median pH was significantly lower in neonates above the median total deceleration area under the curve (AUC; 7.26 vs. 7.32, P = 0.002). Gestational age at delivery was independently associated with total deceleration AUC above median (adjusted odds ratio 1.21, 95% confidence interval 1.09-1.37) controlling for history of previous cesarean delivery and duration of second stage of labor. A significant correlation was found between cord blood pH and total deceleration area (P < 0.001, Spearman correlation coefficient -0.37). CONCLUSION: Among women with postdate pregnancies, the total deceleration area and the mean maximum duration of decelerations were negatively correlated with cord blood pH. Further studies are needed to incorporate deceleration area as a method in predicting fetal acidemia.

Intrapartum deceleration and acceleration areas are associated with neonatal encephalopathy.

OBJECTIVE: To investigate whether an association exists between deceleration and acceleration areas on continuous fetal cardiotocography (CTG) and neonatal encephalopathy (NE). METHODS: A single center, retrospective case-control study was conducted to compare CTG characteristics of low-risk pregnancies (35 weeks of gestation or more), complicated by moderate to severe NE with two matched controls for every case. Controls were matched by gestational age and cord blood pH. We analyzed the intrapartum CTG recordings by calculation of the deceleration and acceleration areas and the ratio between the two. RESULTS: During the period between 2013 and 2019, we identified 95 cases of low-risk pregnancies that were complicated by moderate to severe NE in our center. Thirty-three (34.7%) deliveries were excluded, mostly because of an insufficient duration of the CTG recordings. The remaining 62 cases were matched with 123 controls. We found that NE was significantly associated with an increased total deceleration area, a decreased total acceleration area, and a lower acceleration-to-deceleration ratio. CONCLUSIONS: NE was significantly associated with increased total deceleration area, decreased total acceleration area, and a lower acceleration-to-deceleration ratio, independent of cord blood pH. Development of a computerized real-time analysis of fetal heart rate tracings may contribute to making these measurements a more valid clinical tool.