[Reproducibility of the Doppler ultrasound blood flow profile of the umbilical artery with special reference to threatened premature labor].

The reproducibility of Doppler blood velocity profiles of the umbilical arteries within the umbilical cord is a special problem because of the difficult separation and extreme torsion of both vessels. Resistance-(RI) and pulsatility index (PI) have been assessed on two different locations immediately one after the other in 90 pregnancies with signs for premature labor, including 16 cases with premature rupture of membrane. For comparison the same measurements have been performed in 33 normal pregnancies. There was a significant correlation between the first and second assessment. However, the correlation coefficients of cases with premature labor are lower than in normal pregnancy. This underlines the necessity of at least two repeated measurements for these patients with signs of premature labor.