A comparison of endothelium-dependent relaxation in omental and myometrial resistance arteries in pregnant and nonpregnant women, , ,

OBJECTIVES: The study aimed to compare endothelium-dependent relaxation in the resistance arteries of the uterine vascular bed by use of a systemic comparison and to investigate the role of the endothelium in adaptation to pregnancy in these vascular beds. STUDY DESIGN: Myometrial and omental resistance arteries were collected from 22 normotensive pregnant women and 27 nonpregnant women of reproductive age. On a wire myograph and preconstricted with vasopressin, the arteries were relaxed with the endothelium-dependent vasodilator bradykinin. RESULTS: The omental arteries showed a consistently greater endothelium-dependent relaxation than the myometrial arteries, both in the nonpregnant state (p< 0.0001) and in pregnancy (p = 0.008); pregnancy did not significantly alter this relaxation in arteries from either the myometrial (p = 0.2075) or omental (p = 0.372) vascular beds. CONCLUSIONS: The endothelium-dependent relaxation to bradykinin is less in myometrial resistance arteries than in omental resistance arteries. There appears to be no intrinsic difference between vessels from nonpregnant and pregnant women in endothelium-dependent response to bradykinin. (Am J Obstet Gynecol 1996;175:1307-12.)