Expression of leukaemia inhibitory factor (LIF) during the window of implantation in copper T380A intrauterine device users.

Objective: The mechanism of action of intrauterine devices (IUDs) is not well understood. This investigation was intended to gain further insight into the role of leukaemia inhibitory factor (LIF) in intrauterine contraception. We evaluated the immunohistochemical distribution patterns of LIF in women wearing a copper T380A IUD.

Methods: The immunohistochemical distribution patterns of LIF in women who had been using a copper T380A IUD for different periods of time, two months after removal of the IUD, and in normal fertile women were evaluated. Endometrial biopsies were obtained from four groups of patients according to the duration of T Cu380A IUD use (group I: <5 years, n = 15, and group II: > or = 5 years, n = 15), after IUD removal (group III, n = 15) and normal fertile women (controls, n = 15) during the window of implantation (WOI). Staining intensity of LIF was evaluated using semi-quantitative IRS-scores.

Results: The lowest expression of LIF was observed in women using a copper T380A IUD, being statistically significant compared with the control group (p < 0.05). LIF immunostaining remained abnormal two months after IUD removal.

Conclusions: Copper IUDs can inhibit expression of LIF and they may cause inhibition of the implantation stage, which is crucial for pregnancy.