Anemia-Related Hemogram, Uterine Artery Pulsatility Index, and Blood Pressure for the Effects of Four-Agents-Decoction (Si Wu Tang) in the Treatment of Primary Dysmenorrhea

Abstract

We previously reported pain intensity as the primary outcome of Four-Agents-Decoction (Si Wu Tang) for treating primary dysmenorrhea. We further explored other effects of this formula in accordance with the theory of Traditional Chinese Medicine on anemia-related hemogram parameters for "nourishing blood" and uterine artery pulsatility index (PI) for "blood stagnation." Data were assessed for post-hoc analysis from 76 young women from the Taipei metropolitan area of Taiwan who participated in the randomized double-blind clinical trial. Analysis of variance and t test were used to examine the treatment effect between and within the Four-Agents-Decoction and placebo groups. In addition to pain intensity, anemia-related hemogram parameters, uterine artery PI, menstruation characteristics, and blood pressure were compared. Compared to placebo, biochemical indicators for anemic status did not change differently after the treatment with Four-Agents-Decoction (Si Wu Tang). The changes in uterine artery PI, menstrual pain intensity, and blood pressure were statistically greater in the active treatment group than in the placebo group. In the 25 women receiving ultrasound examination on the same menstruation day, the directions of the changes in both PI and in visual analog scale (VAS) pain intensity aligned well. The changes in the left PI, right PI, and VAS pain intensity in the Four-Agents-Decoction group were -0.391 +/- 0.861, -0.344 +/- 1.03, and -0.251 +/- 2.02 cm; those in the placebo group were 0.208 +/- 1.10, 0.372 +/- 1.06, and 0.438 +/- 2.98 cm, respectively. Inversely, the changes in blood pressure were 11.4 +/- 10.5 mm Hg for systolic blood pressure and 8.36 +/- 8.65 mm Hg for diastolic pressure for the Four-Agents-Decoction group and 6.36 +/- 8.66 and 2.91 +/- 11.2 mm Hg, respectively, for the placebo group. The directions of the changes did not shift, nor did the values change drastically, after adjusting for the level at screening cycle. The anemia status evaluated in conventional medicine does not readily explain the effect of "nourishing blood" by Four-Agents-Decoction (Si Wu Tang) from this exploratory study. Although we did not find strong statistical significance of treatment effect, the decreased PI and extra blood pressure elevation may indicate an improvement of "blood stagnation" in the Four-Agents-Decoction group. The added information warrants a further larger clinical trial with an increased power to enhance our understanding of the efficacy, the dose-response relationship, and the mode of action of this ancient formula for treating primary dysmenorrhea.