[Intrauterine device-induced menorrhagia and endometrial content of prostacyclins]

The endometrial concentration of 6-keto-PGF1 alpha and TXB2 were measured by RIA in women with Tcu-IUD induced menorrhagia (MBL greater than 80 ml) and in levonorgestrel-IUD users with oligomenorrhea or amenorrhea. Non-IUD users with normal menses (MBL less than 80 ml) were chosen as control. It was found that the Tcu-IUD group showed a significantly higher 6-keto-PGF1 alpha concentration than the other two groups (P less than 0.01). Conversely, the TXB2 concentration of levonorgestrel-IUD group was significantly higher than that of the other groups (P less than 0.05). As a result, the 6-keto-PGF1 alpha/TXB2 ratio was much higher in Tcu-IUD group (P less than 0.01). Our results indicated that the unbalance of PGI2/TXA2 ratio may be the direct cause of the IUD-induced menorrhagia.