Objective: To determine whether computer assisted fetal heart rate analysis or the biophysical profile score can provide noninvasive prediction of fetal acidaemia.
Design: Cross sectional study.
Setting: Harris Birthright Research Centre for Fetal Medicine, King's College Hospital School of Medicine, London.
Subjects: Forty-one women with pregnancies complicated by diabetes mellitus.
Interventions: Fetal heart rate (FHR) monitoring with computer assisted analysis, biophysical profile score (BPS) and cordocentesis for measurement of umbilical venous blood glucose concentration and blood gases, up to 24 h before delivery at 27 to 39 weeks gestation.
Results: The mean umbilical venous blood pH was significantly lower than the normal mean for gestation, and was below the 5th centile in 18 pregnancies, including all six cases where the mother had nephropathy and hypertension. The mean pO2 was not significantly different from the normal mean for gestation. There were significant associations between fetal acidaemia and both the BPS (r = 0.46, P < 0.01) and FHR variation (r = 0.42, P < 0.01). However, of the 12 acidaemic fetuses of non-nephropathic mothers, nine had normal BPS and six had normal FHR variation.
Conclusions: In pregnancies complicated by maternal diabetes mellitus, BPS and FHR variation are of limited value in the prediction of fetal blood pH.