Fetal pH value determined by cordocentesis: An independent predictor of the development of antepartum fetal heart rate late decelerations in growth retarded fetuses with absent end-diastolic velocity in umbilical artery

Objective of this study was to establish the relationship in growth retarded fetuses between acid-base status in fetal blood obtained by cordocentesis and time interval between blood sampling and occurrence of antepartum heart rate late decelerations. Eighteen growth retarded fetuses scheduled for cordocentesis were considered for this study. All fetuses were free from structural and chromosomal abnormalities, characterized by absent end diastolic velocity waveforms in umbilical artery and later delivered for the development of antepartum heart rate late decelerations. Regression analysis showed that the time inferval between cordocentesis and delivery was significantly related to pO(2) (r = 0.46; p less than or equal to 0.05) and pH (r = 0.57; p less than or equal to 0.01) delta values but not with pCO(2) values. Stepwise multiple regression analysis demonstrated that the severity of fetal acidosis significantly and independently predicted the length of this time interval even after controlling for confounding variables such as pO(2) values, gestational age, presence of hypertension, or umbilical vein pulsations. The knowledge of this relationship may be useful in the clinical management of growth retarded fetuses.