Clinical management of the fetus with markedly diminished umbilical artery end-diastolic flow

Abstract

This study was conducted to evaluate prospectively a management protocol for fetuses with a markedly abnormal umbilical artery velocity waveform. The study population consisted of fetuses whose systolic/diastolic ratio was greater than 2 SD above the mean for gestational age. The matched control population consisted of fetuses with similar gestational ages, indications for testing, and estimated fetal weights with normal systolic/diastolic ratios. Abnormal Doppler results were used only to determine the frequency of fetal testing. Biophysical profile testing was performed semiweekly on all patients. Patients with absent or reversed end-diastolic flow were admitted for daily testing. The following criteria were used as indications for delivery: (1) worsening maternal condition, (2) oligohydramnios, (3) intrauterine growth retardation with lung maturity, and (4) biophysical profile score less than or equal to 4. Fifty-one patients (7%) had abnormal Doppler blood flow velocity studies. When the study population was compared with the control population at the time of delivery, there were no differences in umbilical artery pH, Apgar score, or incidence of intrauterine growth retardation. However, study patients were delivered at a significantly lower gestational age and lower birth weight and experienced a higher likelihood of neonatal intensive care unit admission. When study patients with documented end-diastolic flow were compared with study patients with no end-diastolic flow, there were no differences in umbilical artery pH, Apgar score, or incidence of intrauterine growth retardation. However, fetuses with no end-diastolic flow had a significantly shorter test-to-delivery interval, lower gestational age, lower birth weight, and more neonatal intensive care unit admissions. There were no perinatal deaths among the study patients. The range of systolic/diastolic ratios for the five patients who failed to follow our protocol for intensive maternal-fetal surveillance was 4.3 to infinity; all experienced fetal death within 18 days. These results suggest that immediate delivery of the fetus with diminished end-diastolic flow may not be mandatory. The combined use of fetal biophysical testing and commonly used criteria for delivery results in acceptable fetal outcome and prolongation of gestational age.