Hepatocyte growth factor (HGF), also known as scatter factor, binds the c-met receptor. It has been shown to be involved in mesenchyme-epithelial interactions. HGF is produced by the villous mesenchyme of the placenta throughout pregnancy and its receptor located on the villous cytotrophoblast cells. In this study the levels of HGF were measured in consecutive samples of plasma taken from pregnant women. Normal pregnancies were compared with intrauterine growth restricted (IUGR) pregnancies (below the third centile). In both groups, the levels of HGF were found to increase significantly as pregnancy progressed and then fall post partum. There was a considerable amount of variation found between individual women but no significant difference (P = 0.65) between the normal and IUGR pregnancies. (C) 1998 W. B. Saunders Company Ltd.