Complexity-loss in fetal heart rate dynamics during labor as a potential biomarker of acidemia

• Published in: Early human development Vol. 90; no. 1; pp. 67 - 71
• Main Authors: Costa, Madalena D, Schnettler, William T, Amorim-Costa, Célia, Bernardes, João, Costa, Antónia, Goldberger, Ary L, Ayres-de-Campos, Diogo
• Format: Journal Article
• Language: English
• Published: Ireland Elsevier Ireland Ltd 01.01.2014
• Subjects: Advanced Basic Science; Cardiotocography; Cardiotocography - methods; Case-Control Studies; Complexity analysis; Data Interpretation, Statistical; Female; Fetal monitoring; Heart rate; Heart Rate, Fetal; Humans; Hydrogen-Ion Concentration; Infant, Newborn; Labor, Obstetric; Male; Metabolism, Inborn Errors - diagnosis; Multiscale entropy; Neonatal and Perinatal Medicine; Pregnancy; Heart rate; Multiscale entropy; Complexity analysis; Cardiotocography; Fetal monitoring
• ISSN: 0378-3782; 1872-6232
• DOI: 10.1016/j.earlhumdev.2013.10.002

Abstract Background Continuous fetal heart rate (FHR) monitoring remains central to intrapartum care. However, advances in signal analysis are needed to increase its accuracy in diagnosis of fetal hypoxia. Aims To determine whether FHR complexity, an index of multiscale variability, is lower among fetuses born with low (≤ 7.05) versus higher pH values, and whether this measure can potentially be used to help discriminate the two groups. Study design Evaluation of a pre-existing database of sequentially acquired intrapartum FHR signals. Subjects FHR tracings, obtained from a continuous scalp electrocardiogram during labor, were analyzed using the multiscale entropy (MSE) method in 148 singletons divided in two groups according to umbilical artery pH at birth: 141 fetuses with pH > 7.05 and 7 with pH ≤ 7.05. A complexity index derived from MSE analysis was calculated for each recording. Results The complexity of FHR signals for the last two hours before delivery was significantly ( p < 0.004) higher for non-acidemic than for acidemic fetuses. The difference between the two groups remained significant ( p < 0.003) when FHR data from the last 30 min before delivery were excluded. Conclusion Complexity of FHR signals, as measured by the MSE method, was significantly lower for acidemic than non-acidemic fetuses. These results are consistent with previous studies showing that decreased nonlinear complexity is a dynamical signature of disrupted physiologic control systems. This analytic approach may have discriminative value in FHR analysis.