Embryo loss

Embryo loss, also called embryo death, is the death of an embryo at any stage of its development. In humans the embryonic stage runs from the second through the eighth week after fertilization. Failed development often ends with the disintegration and assimilation of embryonic tissue in the uterus, a process known as embryo resorption. Loss in the later stages of prenatal development, after organogenesis of the fetus, generally leads to a similar process called fetal resorption, or to miscarriage. Embryo loss frequently happens without any awareness of pregnancy, and the source estimates that 40 to 60 percent of all embryos do not survive.