Embryo loss (also known as embryo death) is the death of an embryo at any stage of its development which in humans, is between the second through eighth week after fertilization.[1] Failed development of an embryo often results in the disintegration and assimilation of its tissue in the uterus, known as embryo resorption. Loss during the stages of prenatal development after organogenesis of the fetus generally results in the similar process of fetal resorption or miscarriage.[2] Embryo loss often happens without an awareness of pregnancy, and an estimated 40 to 60% of all embryos do not survive.[3]