In this study, expression of 5 members of heat shock 70 proteins family (GRP78, GRP75, Heat shock 71 kDa protein, HSPA8 and GRP94), HSP90A and CRYAB (a small heat shock protein) was all increased in the IUGR utero-placenta unit compared with the NBW counterpart, implying that uteroplacental tissues are under more intensive adverse stresses in IUGR fetuses, which may result in their poor development and organ dysfunction. Here, HSP90AA1 is linked to fetal growth restriction.