Transvaginal color Doppler study of uterine blood flow in primary dysmenorrhea

The pain in primary dysmenorrhea is caused by excessive prostaglandin production that leads to vasoconstriction and uterine ischemia. Changes in uterine blood flow are important factors in pathophysiology of primary dysmenorrhea. The aim of the study was to determine if vasoconstriction of the uterine vessels in patients with primary dysmenorrhea is detectable by transvaginal color Doppler ultrasound.

Forty-two women with primary dysmenorrhea and fifty healthy controls were included in this prospective study. Women were examined with transvaginal color Doppler ultrasound on first day of the cycle, once in the follicular and once in the luteal phase. Measurements of pulsatility index in uterine, arcuate, radial and spiral arteries were performed. Student's t-test was used to establish statistical significance between groups.

Women in dysmenorrhea group had significantly higher uterine blood flow indices than healthy controls in all three measurements periods. This includes all vessels studied on the first day of the cycle, the radial and spiral arteries during the follicular phase and the arcuate, radial and spiral arteries during the luteal phase.

We found that women with primary dysmenorrhea have elevated Doppler indices in uterine arteries not only on first day of the cycle but throughout the whole cycle. Therefore we postulated that primary dysmenorrhea is not only the disorder of menstruation but also a disease of a menstrual cycle as a whole.