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 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 >or=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.