Abstract: MicroRNAs （miRNAs） are a class of endogenous non-coding small RNAs with length range of 17-25
nucleotides（nt），which are the most widely studied， and highly conserved in many processes of biological evolution. which play a role in precisely regulating the development，differentiation，proliferation and apoptosis of neurons and other kinds of cell，and involved in immune regulation，neuronal plasticity and re-inhibitory effect of mRNA post-transcriptional processing of signal transduction pathways to increase gene expression. The study indicate that miRNAs participate the important vital process，including fetal development and pregnancy pathological outcome.They receive the differential expression of miRNAs regulation. The level of miRNAs expression have close correlated with pregnancy pathological outcome，including fetal growth retardation，premature rupture of membrane，pre-eclampsia and macrosomia.

Key words: MicroRNAs, Gene regulatory networks, Pre-eclampsia, Fetal growth retardation