About a third of anencephalic fetuses are born alive, but they are not conscious or viable, and soon die. This neural tube defect can be limited by dietary consumption of foliates, and detected prenatally by ultrasound and other means. Many laws permit abortion, on this indication or on the effects of pregnancy and prospects of delivery on a woman's physical or mental health. However, abortion is limited under some legal systems, particularly in South America. To avoid criminal liability, physicians will not terminate pregnancies, by induced birth or abortion, without prior judicial approval. Argentinian courts have developed means to resolve these cases, but responses of Brazilian courts are less clear. Ethical concerns relate to late-term abortion, meaning after the point of fetal viability, but since anencephalic fetuses are nonviable, many ethical concerns are overcome. Professional guidance is provided by several professional and institutional codes on management of anencephalic pregnancies.