This study identified novel associations between foetal size and the endometrial expression of ITGB1 and SPP1. In humans, it has been shown that extravillous trophoblast cells in term placentas which supplied IUGR infants had decreased expression of ITGα2β1, ITGα3β1 and ITGα5β1 integrin receptors compared to those which supplied normally grown infants (Zygmunt et al. 1997). This evidence concerns the gene SPP1 and fetal growth restriction.