OBJECTIVE: To evaluate by analysis of the most serious obstetric cases during a five-year period the contribution of ante-partum CTG and Doppler flowmetry in the diagnosis of foetal risk and to assess the part of risk factors of hypoxia during pregnancy. DESIGN: Retrospective epidemiological analysis. SETTING: Gynaecological and Obstetric Clinic Medical Faculty Palacký University and Faculty Hospital Olomouc. METHOD: In a retrospective analysis based on 6494 deliveries during a five-year period (1996-2000) the authors evaluate a selected sample of 1087 most serious conditions with the diagnosis of imminent foetal hypoxia. In the evaluated group 90.3% of the women had a cardiotocographic examination, 50.8% Doppler flowmetry with assessment of umbilical RI and PI indexes. The diagnosis of neonatal hypoxia was based on evaluation according to Apgar score < 7 and pH of arterial blood < 7.20. The authors compare both diagnostic methods with a common gold standard as regards their ability to predict hypoxia. In the logistic regression model they evaluate risk factors of pregnancy in relation to foetal hypoxia. RESULTS: Clinical manifestations of hypoxia were recorded in 114 neonates (10.5%). Perinatal deaths occurred in 46 infants, 16 were stillborn. Pathological ante-partum CCTG findings are associated with more active approaches (earlier termination of pregnancy, SC, preinduction by prostaglandins). Pathological ante-partum CTG and flowmetry was paradoxically more frequently associated with a better condition of the neonate. Pathological findings of ante-partum CTG were significantly less frequent in neonates with hypoxia than those without it (27%) vs. (40.9%), (relative risk 0.56 [95% CL 0.36-0.88], P = 0.01) while pathological findings of umbilical flowmetry were insignificantly more frequent (34.9%) vs. (33%), (relative risk 1.08 [95% Cl 0.59-1.97], P = 0.9). Both examinations were made in 547 (50.3%) women of the whole group, in 43 (7.9%) hypoxia of the foetus developed. Sensitivity: CTG 32.6%, Doppler 34.9%, Specificity: CTG 51.4%, Doppler 67.3%. Falsely positive CTG 48.6%, Doppler 32.7%. Analysis of risk factors of pregnancy in relation to foetal hypoxia defines by retrospective elimination as significant risks haemorrhage during pregnancy (n = 76, OR 2.35 [95% Cl 1.31-4.23], P = 0.01) and premature delivery (n = 258, OR 2.02 [95% Cl 1.34-3.05], P = 0.0004). CONCLUSION: The value of ante-partum CTG and Doppler flowmetry in the prognosis of neonatal hypoxia is low. The lower rate of pathological findings in affected neonates is probably associated with the fact that part of the hypoxias develop during delivery and cannot be predicted before delivery. The high number of falsely positive findings may by due by the adaptational abilities and reserves of the infant, by a more active approach when there are signs of danger and incorrect interpretation of findings. Premature delivery and haemorrhage are significant risks of neonatal hypoxia.

Gynekologicko porodnická klinika LF UP a FN Olomouc