RESUMO
OBJECTIVES: The purpose of this study was to determine the changes (if any) in the diameter and valve closure time of the lower limb veins in healthy young nulliparous women at different phases of the menstrual cycle. METHODS: Fifty-three young nulliparous women were asked to undergo clinical evaluations and duplex ultrasound examinations of both lower limb veins to monitor changes in the vein diameter and valve closure time at different phases of their menstrual cycles. The vein diameter on B-mode imaging and valve closure time on pulsed Doppler tracing were calculated at days 1 to 4, 14 to 16, and 25 to 28 of the menstrual cycle. Freidman and related samples Wilcoxon signed rank tests were used to determine time-related changes in venous function. RESULTS: The volunteers' mean age ± SD was 20.60 ± 1.90 years, and their mean body mass index was 23.90 ± 4.90 kg/m(2). There was a gradual increase in the vein diameter and valve closure time at the specified phases of the menstrual cycle. Friedman and related samples Wilcoxon signed rank tests for venous segment diameter and valve closure time changes between the different phases of the menstrual cycle were performed and showed statistical significance for each venous segment within each limb (P = .003-.025). Also, when adjusted for body mass index, statistical significance existed for the same venous segments in the same limbs (P =.001-.049). There was no statistical significance for the same venous segments at the same phase of the menstrual cycle between limbs (related samples Wilcoxon signed rank test: P =.079-.97). CONCLUSIONS: During the menstrual cycle, the lower limb veins show an increase in their diameter and valve closure time. These changes are probably mediated by the female sex hormones.