Prostaglandins and cellular reaction in uterine flushings. II. Effect of PG synthesis inhibition in IUD users.

Abstract

The effect of oral administration of indomethacin (100 mg/day), a potent inhibitor of prostaglandin (PG) biosynthesis, on the PG levels and cellular profile in the uterine flushings in response to the use of an IUD (Lippes Loop size C) was studied in sixty women. Indomethacin reduced the cell counts in both follicular and luteal phases of menstrual cycles before and after IUD insertion. The anti-inflammatory drug decreased PGE2 and PGF2 alpha levels in both phases of the cycle before IUD insertion. After insertion, it inhibited only the formation of PGF2 alpha and its 13,14-dihydro-15-keto metabolite in the luteal phase but not in the follicular phase. In long-term users, however, the drugs reduced the levels of all PGs studied in the luteal phase and only PGF2 alpha and its metabolite in the follicular phase. The implications of these findings in the mechanisms of contraceptive action of IUDs and their side effects are discussed.