Doppler waveform patterns of the umbilical artery - screening test for high risk pregnancies

Doppler assessment of umbilical artery waveforms using the peak systolic to end diastolic (S/D) ratio was used to determine if complications associated with impaired trophoblastic invasion of placental bed (i.e. pregnancy induced hypertension and intrauterine growth retardation) could be predicted. Values for S/D ratio of at least 4, 3.5 and 3 at 22-26, 30-32 and ≥ 37 weeks gestation, respectively, were found to be better predictors of such complications. Pregnancy-induced hypertension could be predicted in 63% and growth retardation in 60% cases at 22-26 weeks of gestation.