THE PROGNOSTIC VALUE OF INTRAPARTUM CTG IN DETECTING FETAL METABOLIC ACIDOSIS

Abstract

Perinatal asphyxia remains a serious problem causing significant perinatal morbidity and mortality worldwide and in our country. At present, CTG (cardiotocography) has become the main method of monitoring the fetus during labour. Intrapartum asphyxia is defined as fetal hypercapnia and hypoxemia, which lead to respiratory and metabolic acidosis. The development of metabolic acidosis in the fetus is reflected in the low pH of blood obtained from the umbilical artery shortly after birth. The aim of the study was to assess the prognostic value of CTG in detecting fetal metabolic acidosis. Materials and methods. The study included 200 women in labour and their newborns, who were monitored during labour by the method of intrapartum CTG; an analysis of umbilical arterial blood was also carried out immediately after the birth of the child. Based on the results of the analysis of the newborn's umbilical cord blood, the patients were divided into 2 groups: the main group consisted of 62 patients with fetal/neonatal metabolic acidosis (umbilical arterial blood pH ≤7.12), and the comparison group consisted of 138 patients with their newborns without signs of neonatal hypoxia and metabolic acidosis. Results. The pathological type of CTG was significantly more frequent in the main group, occurring in 36 (58.1%), while in the comparison group it occurred in 12 (8.9%) (OR 14.5; CI 95% 6.67-31.64). The sensitivity of pathological CTG in predicting fetal metabolic acidosis was 75%, and the specificity was 82.9% (RR 6.7; CI 95% 3.73-11.93). The positive predictive value of CTG was 58.1%, and the negative predictive value in predicting metabolic acidosis was 91.3%. Conclusions. The positive predictive value of CTG in predicting fetal metabolic acidosis was low, and the presence of pathological CTG predicted fetal acidosis in only 58.1% of patients. The negative predictive value of pathological CTG in predicting fetal metabolic acidosis was very high (91.3%), which indicates a high probability of the absence of acidosis in the fetus and the newborn in the absence of a pathological type of CTG during labour.