Abstract: Early spontaneous abortion is one of the common pathologic pregnancy in obstetrics.The etiology is complicated，and pathogenesis is not yet clear. Reproductive immunology thinks spontaneous abortion is immune imbalance in maternal-fetal interface，maternal tissues engender immune rejection to fetal tissues.TLR4 is an important kind of pattern recognition receptors in the innate immune system， the activation of TLR4 signal transduction pathway makes some pathological changes in maternal-fetal interface， breaking original immune balance， causing miscarriage. Thus，TLR4-NF-κB pathway may play an important role in the development of early spontaneous abortion. The relationship between TLR4-NF-κB pathway and early spontaneous abortion is reviewed in this paper.

Key words: Abortion, spontaneous, Toll-like receptor 4, NF-kappa B, Pregn