Antepartum fetal testing: a critical appraisal

Recognition of the fetus at risk for death or damage in utero, quantifying the risk, balancing fetal risk against the risk of neonatal complications from immaturity and determining optimal time and mode of intervention, is a cornerstone of modern perinatal medicine. Antepartum fetal testing is essential in making these crucial decisions. The art and science of fetal assessment is fluid. In this treatise, the evolution of testing is reviewed, test accuracy results examined and suggestions for future applications are considered. Composite testing of a range of fetal biophysical variables is an excellent predictor of fetal acidemia and risk of death or damage. Confusion regarding the optimal means of measuring one of these variables, amniotic fluid volume, has been addressed in the literature and contemporary studies from several independent sources indicate that the amniotic fluid index method should be abandoned in favor of the maximal vertical pocket method. It is becoming increasingly more evident that a spectrum of fetal testing modalities based on interrogation of different aspects of fetal adaptive responses to adversity is preferable in fetal testing. Further it is evident that in some fetal diseases, such as intrauterine growth restriction, fetal condition may change acutely and accordingly best outcome is achieved by much more frequent testing. The question of whether intervention for fetal compromise can prevent subsequent neurological sequelae remains open. There has been remarkable advancement in identifying the fetus at risk. The concept of multispectral combined fetal testing including acute biophysical variables, amniotic fluid volume and arterial and venous Doppler flow velocity waveforms is established.