Expression of trophinin in the cycling endometrium and its association with infertility.

OBJECTIVE: To observe the expression of trophinin in the cycling endometrium and investigate its relationship with infertility. METHODS: Trophinin expression in the endometrium was observed in 39 normal cycling women during different menstrual phases and 24 women with infertility during mid-luteal phase by immunohistochemical technique. RESULTS: Trophinin expression was detected in the luteal-phase endometrium of both normal and infertile women, which peaked in the mid-luteal phase. In comparison with normal women, infertile women with endometriosis or unexplained infertility had significantly weakened trophinin expression in the endometrium in the mid-luteal (P<0.001). CONCLUSIONS: Trophinin may play an important role in the process of implantation, and abnormal endometrial trophinin expression might be one of the major causes of infertility.