Foetal umbilical artery doppler versus NST as predictors of adverse perinatal outcome in severe preeclampsia and foetal growth restriction
Keywords:Colour doppler, FGR, NST, Preeclampsia
Background: With the advent of electronic foetal monitoring, a relationship between foetal movement and foetal heart rate was observed and that relationship formed the basis for non-stress test (NST). Doppler USG plays an important role in foetal growth restriction (FGR) pregnancies where hemodynamic rearrangements occur in response to foetal hypoxemia. It is now proved that significant Doppler changes occur with reduction in foetal growth at a time when other foetal well-being tests are still normal. This study was done to find out the comparative usefulness of Doppler and NST in the management of FGR and severe preeclampsia and subsequent correlation with perinatal outcome.
Methods: This prospective study was conducted on pregnant women with severe preeclamsia and/or FGR beyond 30 weeks of gestation at AHRR Delhi. 50 pregnancies complicated with severe preeclampsia and/or FGR beyond 30 weeks of gestation were selected. Patients meeting the inclusion criteria were subjected to NST. Umbilical arterial Doppler flow was obtained at weekly or twice weekly interval depending on the severity by pulsed wave color doppler indices were measured during foetal apnea by the same examiner at the free loop site where the clearest waveform signal could be visualized. Of 3 measurements, the mean average of S/D ratio was recorded and followed up with serial Doppler assessment and non-stress test. Data was collected and statistical analysis was carried out.
Results: The Doppler showed changes earlier than NST giving a significant lead time of up to 20 days with an average of 4.94 days. The UA S/D had the highest sensitivity (88%) and diagnostic accuracy (94%) in predicting the adverse perinatal outcome. The sensitivity and specificity of Doppler as compared to NST was 82.6% and 63.0% respectively with a diagnostic accuracy of 72%. The Doppler has negative predictive value of 80.95% and positive predictive value of 65.5%. Color Doppler has diagnostic accuracy of 72%. The mortality rate in reversal of diastolic flow was 77.77% and in absent UA flow was 16.66%. 12% foetuses were found to have AEDV in UA and among them 66.66% had both FGR+PE as maternal complication. There was 83.33% rate of LSCS, 16.66% neonatal mortality rate, 83.33% NICU stay rate and 66.66% complication rate in neonates. Whereas 18% had REDV and among that 88.88% had both FGR+PE as maternal complication, a similar rate of LSCS, 77.77% rate of neonatal mortality, 100 % NICU stay and 66.66% complication rate in the neonates.
Conclusions: Combined foetal testing modalities such as Doppler, NST and biophysical profile provide a wealth of information regarding foetal health. Integrated foetal testing would be ideal for individualized care of the preterm compromised foetuses for timed intervention.
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