A role for prostacyclin (PGi2) in excessive menstrual bleeding.

The synthesis of prostanoids from arachidonic acid incubated with endometrium alone or together with myometrium was studied in women with excessive menstrual blood-loss (range 57--186 ml, median 86 ml). Production of prostaglandins F2 alpha, E2, and D2 was similar to that observed for the endometrium of women with normal periods (range 5--50 ml; median 11 ml). However, the endometrium from women with excessive menstrual blood-loss was more effective than endometrium from women with normal menstrual blood-loss at enhancing the production by a control preparation of myometrium of 6-oxo-prostaglandin F1 alpha, the stable metabolite of prostacyclin. The ability of the uterus to generate prostacyclin, a prostaglandin known to inhibit platelet aggregation and stimulate vasodilatation, may influence the degree and duration of menstrual bleeding.