Objectives: To assess endothelial function and vascular mechanical properties in normotensive pregnant women with high resistance in the uteroplacental circulation.
Design: Cross-sectional prospective study.
Setting: Doppler ultrasound laboratory at university department of obstetrics and gynaecology referral centre for high risk pregnancies.
Participants: Forty-two caucasian normotensive pregnant women: 23 with uncomplicated pregnancies and 19 with bilateral uterine artery notches.
Methods: Flow-mediated dilatation of the brachial artery was measured by ultrasonography at 25 gestational weeks. Concentrations of nitrite and nitrate in the plasma were established at 25 and 32 gestational weeks. The elastic properties of the common carotid artery, abdominal aorta and popliteal artery were measured with an ultrasonic echo-tracking system.
Results: Flow-mediated dilatation at two minutes after cuff deflation was significantly lower in the bilateral notch group compared with the control group, 8.3% and 13.7%, respectively (P = 0.0007). The ability to sustain vasodilatation was reduced in the bilateral notch group (P = 0.02). Lower values of nitrite and nitrate in the plasma were found at 32 gestational weeks in the bilateral notch group than in the control group (mean 24.76 microM/L (SD 5.6) and 30.93 microM/L (8.2), respectively; P = 0.008). Nitrite and nitrate levels tended to be lower in the bilateral notch group even at 25 gestational weeks (29.45 microM/L (8.3) and 35.73 microM/L (11.0) in the bilateral notch and control group, respectively; P = 0.09). There was no difference in aortic, carotid or popliteal elasticity between the two groups.
Conclusions: Healthy normotensive pregnant women with bilateral uterine artery notches show impaired endothelial function, but no differences in vascular mechanical properties.