This chapter describes a study for the Doppler spectral analysis of cerebral blood flow in preterm infants and the relationship to intraventricular hemorrhage (IVH). IVH continues to be a major cause of mortality and morbidity in preterm infants. The study group comprised 25 normal preterm infants without significant respiratory, cardiovascular, or neurological problems and 32 infants who developed IVH. The healthy infants had a mean gestational age of 32.0 weeks and a mean birth weight of 1740 g, while the infants in whom IVH occurred had a mean gestational age of 29.3 weeks and a mean birth weight of 1300 g. Analysis of the pulsatility index (PI) of the common carotid artery showed a lower value prior to the occurrence of IVH with the PI also being reduced at the time of hemorrhage. Subsequent to the development of IVH, the PI did not differ significantly from the healthy preterm infants. The blood flow velocity waveforms of the anterior cerebral artery demonstrated no difference in the PI before IVH was diagnosed and the control values. It is found that when IVH occurred, however, the PI was significantly reduced.

SummaryA combination of pulsed echo and continuous wave Doppler ultrasound was used to obtain blood flow velocity signals from the umbilical arteries of 10 patients during uncomplicated spontaneous labour. Audio frequency analysis of these signals yielded fetal blood velocity waveforms. Analysis of these waveforms demonstrated that placental vascular resistance to feto‐placental blood flow is not altered by uterine contractions, artificial rupture of the membranes, the infusion of oxytocin nor the administration of analgesia during uncomplicated labour.

A combination of pulsed echo and continuous wave Doppler ultrasound was used to obtain blood flow velocity signals from the umbilical arteries of 18 normal patients from the 16th until the 40th week of pregnancy. Audio frequency analysis of these signals yielded fetal blood velocity waveforms. Analysis of these waveforms demonstrated that the placenta is an organ of low vascular resistance and that placental resistance to blood flow declines with advancing gestational age in normal pregnancy.