Fig. 1.
Uterine NK cells stimulate fetal growth via growth-promoting factors. NK cells are abundant in the uterus during pregnancy. The study by Fu et al.5 now suggests a novel role for NK cells in the uterine microenvironment. Uterine NK cells produce growth-promoting factors. During aging, the secretion of growth-promoting factors by NK cells is reduced and affects fetal development. Future studies will reveal in detail the cellular and molecular mechanisms involved in fetal growth in the uterine microenvironment