Intrauterine Deaths in High-Risk Pregnancies with Normal and Borderline Umbilical Artery Doppler Flow Velocity Waveforms

ABSTRACT

Objective. To investigate the use of a personal computer (PC)-based; continuous-wave Doppler device by a trained midwife at the fetal evaluation clinic at a tertiary hospital to assess flow velocity waveforms (FVWs) of the umbilical artery flow in referred women. Methods. Pregnant women referred for suspected poor fetal growth were evaluated from June 2002 through December 2004. The Umbiflow device (still prototype; developed by CSIR/MRC/Stellenbosch University); consisting of a Pentium 3 PC with an ultrasound transducer plugged into the USB port; was used to analyse the FVW of the umbilical artery. Pregnancies in which the resistance index (RI) was 75th percentile (P75) were not further evaluated for fetal well-being unless the clinical condition of the mother had changed. Pregnancies with an RI P75 were followed up according to a specific protocol. Primary endpoints were intrauterine death and intrauterine growth restriction. Results. Doppler FVWs were assessed in 955 pregnancies. The RI was P75 in 529 participants (55.4); between the P75 and P95 percentile in 350 (36.6) and P95 in 53 (5.5). In 23 cases (2.4) end-diastolic flow was absent or reversed (AREDF). Intrauterine death within 1 week of the test occurred in 1; 4; 0 and 2 women respectively in these four groups; and 16.7; 34.5; 54.9and 65.5respectively gave birth to infants that were small for gestational age. Conclusions. Intrauterine death; within 1 week of the test; was extremely rare when the RI was P75 (0.2). Relatively more deaths within a week of the Doppler examination occurred in the P75 - P95 group. This group should be regarded as being at high risk and needs careful antenatal surveillance