The role of the haemostatic system in relation to menstrual bleeding is poorly understood. Platelet retention to glass beads and plasma concentrations of 6-oxo-PGFα and thromboxane B2 were measured in uterine and peripheral venous blood obtained from 18 women undergoing abdominal hysterectomy. Concentrations of 6-oxo-PGFα were significantly (p<0.01) higher in uterine (1.4 ± 0.3 ng/ml, mean ± SEM) than in peripheral vein blood (0.2 ±0.1 ng/ml) as was the level of thromboxane B2 (0.5 + 0.1 and 0.2 ± 0.1 ng/ml, respectively). Platelet retention in uterine vein blood (11 ± 4%) was significantly lower than in peripheral blood (42 ±4%; p<0.01) and the degree of platelet retention correlated inversely with the plasma concentration of 6-oxo-PGFα (r −0.43; p<0.01). There was a significant rank correlation between time since menstruation and concentrations of 6-oxo-PGFα in uterine (τ + 0.69; p<0.001) and peripheral (τ + 0.56; p<0.05) vein blood. The results indicate that an increased local production of prostacyclin (PGI2) relative to thromboxane A2 at the time of menstruation could contribute to the mechanism of uterine bleeding.
Keywords
Prostacyclin - Thromboxane B
2
- Uterus - Menstruation - Platelets
