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One-hundred and eighty-seven single pregnancies, at full term determined accurately and confirmed by ultrasound before 17 weeks of amenorrhea and which were proceeding normally were monitored every 2 days after the expected end of term. This was done by conventional methods and in 132 cases by determining a placental resistance index (R = D/S). All the deliveries were carried out under monitoring and the infants examined by a pediatrician. The umbilical index at 280 to 300 days of gestation was found to be constant and equal to R = 0.52 +/- 0.041 (n +/- D) and the signs of fetal distress and post-maturity increased beyond term. In the first 80 pregnancies studies in this way, the determination of the value of the index R was not included in the decision-making process. Twelve of the 14 cases of fetal heart rate arrhythmia during delivery and all recorded cases of post-mature clinical signs and neonatal acidosis occurred when the index was above RI = 0.54. The next 107 pregnancies were randomly divided into two groups. In the 52 pregnancies in which the Doppler revealed an index at two consecutive determinations in excess of 0.54, this was taken to be a criterion for the induction of childbirth. In this group, some of the women gave birth earlier, without any increase in the number of Caesareans and this resulted in fewer post-mature infants.(ABSTRACT TRUNCATED AT 250 WORDS)

Foetal well being is assumed in normally proceeding pregnancies. In pregnancies with a risk of foetal distress, the obstetrician now has the possibility of carrying out foetal cerebral hemodynamic exploration in order to reach a short-term prognosis. The brain of the foetus is a hemodynamically privileged site in cases of hypoxic foetal distress; this brain-sparing effect gives rise to Doppler velocimetric signs which are seen in animal and human foetuses. Cerebral resistance, measured in Doppler velocimetry from the resistance index R = (S.D)/S falls at the beginning of the last third of pregnancy, but remains higher than placental resistance. This is due to the considerable development of foetal brain vascularization from this time forward. Inversion of the ratio between the cerebral index (CRI) and the umbilical index (PRI) and a marked reduction of the cerebral index below the normal range demonstrates the brainsparing effect during hypoxic distress. In cases of delayed intra-uterine growth, this signs is linked to a high probability of forthcoming acute foetal distress (AFD). In hypertension of pregnancy, the fall in CRI is closely correlated with a high Caesarian rate due to AFD and a higher morbidity level and neo-natal sequelae. The prognosis for these foetuses therefore depends on their gestational age: it is good after 34 weeks of amenorrhea, but remains doubtful between 28 and 34 weeks of amenorrhea. In these cases, the administration of oxygen to the mother for 20 minutes (FLO2 = 70%, 8 l/min) constitutes a prognostic test. The foetuses whose CRI is corrected have a better prognosis than the others, if the pregnancy continues up to the change in foetal cardiac rhythm.(ABSTRACT TRUNCATED AT 250 WORDS)

The authors carried out a combined study using Doppler Flow Studies of the umbilical and fetal anterior cerebral arteries in 26 pregnancies which were complicated by maternal hypertension. Using the ratio between the cerebral and the umbilical blood flow it may be possible to diagnose intra-uterine growth retardation more accurately than using classical measurements. An inversion of the ratio between the cerebral and the umbilical flows has a great prognostic value with a sensibility of 91.6%, a specificity of 87.5% and a positive predictive value of 84.6% with a negative predictive value of 93.13%. There may however quite often be a lengthy interval of time between the appearance of change in the ratio and the appearance of fetal distress, so that this sign can only be one indication for delivery of the fetus.