Prostaglandins in menstrual fluid in menorrhagia and dysmenorrhoea

Menstrual fluid was collected in vaginal cups inserted for 2 h during the first 2 days of menstruation and menstrual serum concentrations of prostaglandins PGF_2α and PGE₂ were measured by radio‐immunoassay. In 16 women from whom menstrual fluid was collected on both days, PGF_2α and PGE₂ concentrations were significantly higher on day 1 than on day 2. The highest concentrations of PGF 2α and PGE₂ were found in dysmenorrhoeic women on day 1. In non‐dysmenorrhoeic women, the amount of PGF_2α and PGE₂ collected in 2 h correlated directly with total menstrual blood loss. There was no statistically significant difference in the amount of prostaglandins collected in 2 h in pain‐free menorrhagic women and dysmenorrhoeic women with normal loss. There was also no significant 9‐ketoreductase or 9‐hydroxydehydro‐genase activity present in menstrual fluid which could suggest PGE₂ to PGF_2α interconversion.