Exploiting the significance of uterine natural killer cells in pregnancy

Pregnancy is a complex physiological phenomenon involving maternal-fetal communication. Uterine natural killer (uNK) cells established a profound lymphocyte population in the early pregnant uterus. These cells are closely linked with extravillous trophoblast (EVT) and spiral arteries and play a vital role in remodeling spiral arteries, trophoblast invasion and placental development. The uNK cells are the potent releasers of cytokines and growth factors; with close association to EVTs in the maternal-fetal interface, it drives an essential function in the trophoblast. At present, limited studies are available explaining the significance of uNK cells in normal pregnancy and pregnancy-associated problems. This review article elucidates the descriptive role of uNK cells in pregnancy problems and their crosstalk with other immune cell components. Moreover, we will also discuss whether uNK cells become a threat to pregnancy with clinical evidence.