title: [Structure and function of the cardiotocographic score (CTG-score) calculated by the "quantitative cardiotocography" computer method. Determining the significance of its components for the accuracy of the estimates for the ph of the fetus].
abstract: BACKGROUND
  In the last three years "quantitative cardiotocography" has become the main method for fetal monitoring during late pregnancy and birth in Sheynovo hospital - Sofia, Bulgaria. Our previous studies presented opportunities for increasing the diagnostic potential of the methodology. In this paper we offer a new approach to further improve the accuracy of prognostic values for fetal pH during labor. This is achieved by analyzing the individual components of the CTG-score (microfluctuation - OSZ, basic fetal heart rate - FRQ and decelerations - DEC). Several groups of CTG-scores have been formed, according to the composition of the score and the correlation between forecast and actual results for the pH of the fetus.
  
  
  METHODS
  For each of the stored 171 recordings we compared the CTG-score, produced prior to the delivery, with the pH measured in the umbilical artery (UA) before cutting the umbilical cord. As fetal pH forecast is based strictly on the CTG-score value, the difference between actual and prognostic results for the pH actually shows how accurate is the CTG score itself. We used standard deviation (Std. deviation) to assess this variability.
  
  
  RESULTS
  We defined several groups of CTG-score based on its composition and the respective standard deviations. Each group includes CTG-scores with no significant statistical difference between the calculated standard deviations: CTG-score with low (composed of OSZ; Std. Dev. 0.065), satisfactory (composed of OSZ + FRQ and FRQ; Std. dev 0048 and 0044), high (composed of OSZ + DEC and DEC; Std. dev 0032 and 0027) and very high (composed of FRQ + DEC and OSZ + FRQ + DEC; Std. dev. 0019 and 0012) predictive value. We observed a substantial variety in the prognostic results, depending on which components of the CTG-score are involved in the evaluation of pH.
  
  
  CONCLUSIONS
  The composition of the CTG-score seems to be crucial for the accuracy of the prognostic fetal pH values. In order to organize the gathered information it is necessary to develop clinical practice guidelines which would allow us to cohere the obstetric behavior with data readings from the quantitative cardiotocography method.
authors.forename: P
authors.initials: P
authors.lastname: Ignatov
authors.forename: B
authors.initials: B
authors.lastname: Atanasov
mesh_terms: D002031:Bulgaria; D015148:Cardiotocography / Q000379:methods*; D005260:Female; D005312:Fetal Blood / Q000737:chemistry*; D005323:Fetal Monitoring / Q000379:methods*; D006801:Humans; D006863:Hydrogen-Ion Concentration; D011247:Pregnancy; D012680:Sensitivity and Specificity