Late termination of pregnancy (TOP),[1] also known as postviability abortion,[2] late-term abortion,[3] later-term abortion,[4] partial-birth abortion, ITOP,[5] or simply abortion[6] are terminations of pregnancy which are performed during a later stage of pregnancy. Late termination of pregnancy is more controversial than abortion in general because they result in the demise of a fetus that is more developed and sometimes able to survive independently. Given the complex, gradual nature of human fetal development, the definition of "late" in this context is not precise, and different medical publications have discussed the varying gestational age points that can be involved.