Human chorionic gonadotropin promotes recruitment of regulatory T cells in endometrium by inducing chemokine CCL2.

•Intrauterine infusion of hCG increased the endometrial Tregs and CCL2 expression.•CCL2 expression and Tregs migration were significantly increased with hCG stimulation.•Tregs migration was decreased with CCL2 siRNA or CCR2 antagonist treatment.•Intrauterine infusion hCG promotes the recruitment of Tregs by inducing CCL2.