Review: The role of leukaemia inhibitory factor in the establishment of pregnancy.

Leukaemia inhibitory factor (LIF) is a pleiotrophic cytokine required for blastocyst implantation in mice. Uterine expression of LIF and that of its receptors has been demonstrated in a number of mammalian species indicating that LIF may have widespread importance in the establishment of pregnancy. The variations in the reaction of the uterus in preparation for and during implantation are considerable between species and understanding the differences and similarities assists in the interpretation of how this cytokine functions. Recent studies suggest that reduced endometrial LIF contributes to human infertility. Studies also demonstrate a potential role in placentation and fetal development. Thus, LIF has become an important cytokine warranting further investigation in the human. It is anticipated that when the mechanisms underlying normal embryonic and endometrial development are elucidated, fertility and infertility will be more precisely understood and hence able to be effectively controlled.