Regional hemodynamic adaptation during the menstrual cycle

Abstract

Objective: To determine whether regional differences exist in uterine and systemic hemodynamic responses to the menstrual cycle, whether the hormonal environment correlates with the changes, and whether uterine artery hemodynamic adaptation depends on the side of ovulation.

Methods: Twenty nulliparas had transvaginal Doppler ultrasonographic assessment of the uterine and upper-extremity radial arteries at three time points in each of two menstrual cycles. Doppler indices (peak systolic velocity, end-diastolic velocity, time-averaged maximum velocity, resistance index [RI], and blood flow) were measured in the radial and uterine arteries. Women were examined in the menstrual (cycle day 2-3), follicular (cycle day 9-10), and luteal phases (cycle day LH surge plus 9-10). At each time, serum estradiol (E2) and progesterone were measured by radioimmunoassay. Statistical analyses were repeated-measures analysis of variance and the Fisher least significant difference procedure.

Results: Thirty-four nonconception ovulatory cycles were evaluated. Blood flow in each uterine artery increased significantly from a mean (+/- standard deviation) of 22.4 +/- 7.3 mL/minute in the follicular phase to 30.7 +/- 13.7 mL/minute in the luteal phase, which coincided with a reduction in the RI. The changes were independent of the side of ovulation. The radial artery did not parallel these changes (follicular blood flow of 27.2 +/- 13.9 mL/minute; luteal blood flow of 24.7 +/- 10.5 mL/minute). We did not identify any significant correlation between these changes and serum E2 or progesterone concentrations.

Conclusion: We identified differences in the hemodynamic responses of the uterine artery compared with the radial artery during the menstrual cycle. We believe the difference indicates distinct regional control of vascular response during the menstrual cycle.