Relationship between fetal biophysical profile and fetal cord blood acid-base status obtained by cordocentesis

Moon, Jeong Bin; Park, Joong Shin; Jun, Jong Kwan; Yoon, Bo Hyun; Syn, Hee Chul

Abstract

OBJECTIVE
Fetal biophysical profile is widely used antenatal test for fetal wellbeing, but its biochemical background is not well known. The purpose of this study is to examine the relationship of fetal biophysical profile and cord blood acid base status including gas analysis using cord blood obtained by cordocentesis, by which the biochemical background of fetal biophysical profile can be understood. STUDY DESIGN: 121 pregnant women received cordocentesis for various indication, of whom the fetuses were evaluated with fetal biophysical profile just before the cordocentesis. Cord blood obtained by cordocentesis was analyzed for acid-base and gas status. The results of both tests were compared by appropriate statistical method.
RESULTS
Fetal biophysical profile showed definite correlation with the results of cord blood acid-base and gas analysis (p<0.001). Fetal biophysical profile was not a sensitive study for the diagnosis of fetal acidemia, but the test could be used for the diagnosis of severe fetal acidemia. Variables of fetal biophysical profile responded to acidemia differently and there were gradual changes among the variables according to the degree of acidemia. Gestational age was important factor for the normality of nonstress test, even after adjustment of pH level. Anomaly did not affect the fetal biophysical profile and fetal biophysical profile was determined mainly by fetal metabolic status.
CONCLUSION
Fetal biophysical profile score is a useful noninvasive antenatal test reflecting fetal acid base status, effective for the diagnosis of severe acidemia, probably affected by fetal gestational age, but not by fetal anomaly.