Umbilical artery Doppler waveform indices from normal pregnant women are related to vasodilatation of placental chorionic plate small arteries.

Blood flow control within the fetoplacental circulation is poorly understood despite the essential role of the placenta in pregnancy. Our study compared an in vitro assessment of placental chorionic plate small artery function with in vivo measures of umbilical artery blood flow.Umbilical artery Doppler waveform analysis was performed on women (N = 8) with uncomplicated pregnancies within 24 hours of delivery. Small arteries (n = 25) were dissected from the placental chorionic plate from biopsies at term and studied using parallel wire myography.Chorionic plate arteries developed maintained constrictions to the thromboxane-mimetic U46619. Nitric oxide (NO) donation with the endothelial-independent agent sodium nitroprusside elicited significant relaxation compared to paired control vessels. This vasodilatation correlated significantly with both pulsatility and resistance indices measured in the umbilical artery.We conclude that Doppler indices in the umbilical artery are inversely proportional to the maxi...