Uterine fibroids--do size and location determine menstrual blood loss?

Objective: To investigate any potential effect of fibroid size and distribution on menstrual blood loss (MBL).

Study Design: Retrospective comparative study of 50 women with symptomatic fibroids who underwent uterine imaging and objective MBL measurement prior to uterine artery embolisation between 1999 and 2002.

Setting: West of Scotland Gynaecology and radiology departments.

Method: Uterine imaging was by magnetic resonance imaging (MRI) in all but one case and MBL was performed using the alkaline haematin technique. Fibroid characteristics were assessed by an experienced radiologist unaware of the MBL measurements.

Results: Thirty-three (66%) women had objective menorrhagia with a MBL in excess of 80 ml per period. The commonest location of fibroids was intramural; these particular fibroids also had the largest diameter and the greatest uterine volume. There was a negative relationship between MBL and the diameter of the largest fibroid (r = -0.419, P < 0.01). All but two women (both of whom had subserosal fibroids alone) demonstrated distortion of the uterine cavity. All women with submucosal fibroids presented with menorrhagia.

Conclusion: This study found that MBL correlated with neither fibroid size nor location. However, all the women with sub-mucosal fibroids had menorrhagia with a MBL greater than 80 ml.