Evaluation of the use of umbilical artery Doppler flow studies and outcome of pregnancies at a secondary hospital

Objective. To investigate the use of a personal computer (PC)-based, continuous-wave Doppler machine by a trained midwife at a secondary hospital to assess umbilical artery flow velocity waveforms (FVW) in referred women. Methods. Pregnant women referred for suspected poor fetal growth were evaluated from June 2002 through December 2004. The Umbiflow (R) apparatus, consisting of a Pentium 3 PC with an ultrasound transducer plugged into the USB port and software, was used to analyze the FVW of the umbilical artery. Pregnancies in which the resistance index ( RI) was < 75(th) percentile (P75) were not further evaluated for fetal well-being unless the clinical condition of the mother changed. Pregnancies with an RI >= P75 were followed up according to a specific protocol. Primary end points were intrauterine death and intrauterine growth restriction. Results. A total of 572 singleton pregnancies were followed up. Significantly more infants were small-for-gestational-age when the RI was > P95 (55.6%) than those between P75 and P95 (41.2%) or < P75 (27.2%). Perinatal mortality rates were 13.2, 39.1 and 41.7 for women with RIs < P75, P75 - 95 and > P95, respectively. Conclusions. A normal Doppler FVW of the umbilical artery is less likely to be followed by perinatal death.