Value of inferior vena cava Doppler waveform analysis for prediction of neonatal outcome

The objective of this article is to determine the value of the inferior vena cava preload index (IVC) to predict neonatal outcome and compare it to other biophysical methods of antenatal surveillance. A clinical outcome study of patients referred to the author's institution for Doppler velocity blood flow studies was undertaken by comparing the ability of three antenatal surveillance tests: the nonstress test (NST); umbilical artery S/D ratio (UA); and the ratio of the middle cerebral artery to umbilical artery S/D ratios (MCUA) to predict poor neonatal outcome to the ability of the IVC to predict poor outcome. Patients were followed serially and neonatal outcome data was tabulated. Those patients that delivered within 10 days of their last study were included in the analysis. Seventy patients met the inclusion criterion. Neonatal outcome based on the results of the IVC as compared with outcome based on the results of the NST, UA, and MCUA tests. Odds ratios (with 95% confidence limits) for significant neonatal morbidity predicted by each test were: NST: 2.6 (0.14-14.6); UA: 5.7 (1.7-18.8); MCUA: 3.6 (1.1-13.1); and IVC: 4.1 (1.3-13.2). Logistic regression analysis indicated that the combination of MCUA and IVC was the best method of predicting poor neonatal outcome. This study of the utility of fetal IVC suggests that this noninvasive method of antenatal surveillance may provide an additional sensitive method of evaluating the status of the high-risk fetus.