Developmental changes in spiral artery blood flow in the human placenta observed with colour Doppler ultrasonography

This study confirms that ultrasound can be used to study the gestation dependent changes in the haemodynamics of the placental basal plate predicted, but not proven, by histologic data. The bi-modal distribution of jet lengths suggests that mega-jets are a separate entity to 'normal' jets. That they are significantly wider than 'normal' jets and yet maintain the same velocity of blood flow suggests that they have a greater volume of blood flow. The mechanism for this is hypothesised and their apparent relationship with simple placental lakes discussed.