Fetal biophysical profile score. VI. Correlation with antepartum umbilical venous fetal pH.

Abstract

Our objective was to determine the relationship, if any, between the fetal biophysical profile score and antepartum umbilical venous pH. This was a prospective observational study conducted concurrently in two centers and involving two discrete high-risk groups of fetuses. Fetal biophysical profile scores were compared with umbilical venous pH values measured in blood obtained by immediate cordocentesis. A total of 493 paired observations of biophysical profile score and pH were made; 104 observations were of fetuses with intrauterine growth retardation and 389 observations were of fetuses with alloimmune anemia. In both data sets there was a highly significant linear correlation between biophysical profile score and umbilical venous pH. Poor biophysical profile score performance (a score of 0 of 10) was always associated with a pH < 7.20, whereas the pH was always > 7.20 when the biophysical profile score was 10 of 10. Sequenced sensitivity of short-term biophysical variables in the detection of acidemia was observed. The fetal biophysical profile score accurately predicts antepartum umbilical venous pH.