pregnancy loss pregnancy loss pregnancy loss is the loss of an embryo or fetus. the terms early pregnancy loss and late pregnancy loss are often used but there is no consensus over their definitions. unintentional pregnancy loss miscarriage toxic abortion, caused by pollution or chemical exposures implantation failure molar pregnancy embryo loss fetal resorption blighted ovum vanishing twin stillbirth pregnancy loss through termination foeticide abortion selective reduction to reduce the number of fetuses in a multiple pregnancy hysterotomy abortion, a surgical abortion of a non-viable fetus performed similar to a cesarean section late-term abortion self-induced abortion sex-selective abortion forced abortion child destruction