Menorrhagia and uterine artery blood flow

Menorrhagia is a significant problem in women of reproductive age. In half of the cases no specific aetiology is known. Vascular factors play a role but remain poorly understood. We chose to study whether any association exists between the flow impedance of uterine arteries and the amount of menstrual blood loss. The study population consisted of 60 spontaneously menstruating 35- to 49-year-old women without endometrial hyperplasia, polyps, or submucous fibroids. The pulsatility index (PI) from uterine arteries, arcuate arteries, and radial arteries was measured by transvaginal colour Doppler. Menstrual blood loss was measured by the alkaline haematin method. A significant inverse correlation was found between uterine artery PI and the amount of menstrual blood loss, suggesting that women with lower uterine flow impedance bleed more. A regression model confirmed that this association was specific and not explained by uterine size, fibroids or any other of the 11 potential confounders included in the model. The correlation between uterine artery PI and amount of menstrual blood loss suggests that vascular factors may be involved in the pathogenesis of menorrhagia.