string: …to expression in the fetus, Igf2 is expressed by the placenta (Constância et al. 2002) and mice lacking the placenta-specific Igf2 transcript show IUGRaswell as placentas that are small and have altered nutrient transport (Constância et al. 2002; Sibley et al. 2004; Sferruzzi-Perri et al. 2011).