[The role of progesterone in human early pregnancy is mediated by insulin-like growth factors binding protein1-3].

Objective: To determine whether the functional role of progesterone in human early pregnancy is mediated by progesterone receptor(PR) and insulin-like growth factor binding protein 1-3(IGFBP1-3).

Methods: Sample collection was conducted in accordance to the principle of informed content. Decidua and villi were obtained from 48 healthy women in 5-7 weeks of pregnancy, and endometrium in mid-secretory phase was obtained as control. The serum levels of progesterone were detected by radioimmunoassay, and the expressions of IGFBP1-3 and progesterone receptor were detected by immunohistochemistry (LsAB)and quantified by a computer image analysis system.

Results: Serum progesterone increased gradually and reached peak level in 5-6 weeks, which was significantly higher than that during the mid-secretory phase (P<0.05). The expression of progesterone receptor in luminal epithelium and decidual cells had significant correlations with serum progesterone, but its expression in glandular epithelium and trophoblast cells had no correlations with serum progesterone. IGFBP1-3 in luminal, glandular epithelium, and decidual cells had significant correlations with serum progesterone, but their expression in trophoblast cells had no correlations with serum progesterone.

Conclusion: Progesterone plays an important role in the support and maintenance of early pregnancy, and its effect may be mediated by progesterone receptor and IGFBP1-3, in decidual-trophoblast interface.