We tested the hypothesis that the uterine artery vasoconstrictor response to graded exercise during early gestation would be similar to the nonpregnant state and would be attenuated at mid and term gestation. Responses to graded treadmill exercise were measured in 6 female NZW rabbits in the nonpregnant (NP) state, at day 10, day 20, and day 28 (term) of gestation. Uterine artery blood flow (UtBF) was measured continuously with a Transonic flowprobe. Rabbits performed a graded exercise test to voluntary exhaustion (max exercise) starting at 7 m/min, 7% grade. UtBF and uterine artery conductance (UtC) decreased similarly during graded exercise (P<0.01) in the NP state [At max exercise: -40 % (SD 20) for UtBF and -45% (SD 14) for UtC] and at day 10 of gestation [At max exercise: -48% (SD 17) for UtBF; -56% (SD 14) for UtC]. In contrast, there was little change in UtBF or UtC during graded exercise at day 20 [At max exercise: -4% (SD 17) for UtBF, P<0.05 vs. NP; -16% (SD 12) for UtC, P<0.01 vs. NP] and at day 28 [At max exercise: +7% (SD 15) for UtBF, P<0.01 vs. NP; -2% (SD 24) for UtC, P<0.01 vs. NP], indicating substantial attenuation of the uterine artery vasoconstrictor response to exercise. At rest, UtC responses to graded doses of IV phenylephrine were unaffected by the stage of gestation, which suggests that uterine artery responsiveness to ₁-adrenoreceptor stimulation is preserved through gestation. Normal pregnancy in the rabbit is associated with attenuation of the uterine artery vasoconstrictor response to graded exercise that develops by mid-gestation.