[Doppler umbilical artery velocimetry during labor in normal pregnancies]

A prospective study using umbilical artery velocimetry was carried out with continuous Doppler wave forms coupled to a spectral analyser (D.F.P.C. Slous) with placement of Pourcelot's placental resistance index in 94 deliveries at term of singleton normal pregnancies. Neither the position of the patient, rupture of the membranes, epidural anaesthesia, oxytocics, Dextrofemine, nor the length of labour, change the placental resistance levels during the delivery. These remain constant and equal R = 0.51 +/- 0.10 (M +/- 2 DS) whatever the appearance of the RCF at the start of labour, during dilatation and during the delivery. We considered term as being between the 38th and the 42nd week of amenorrhea. Our results show that changes in the index of resistance in the umbilical artery do not help in assessing deliveries in normal pregnancies.