Reasons for late abortion: acardius
Acardius means developing without a heart. As long as the fetus depends on the mother for oxygenated blood and nutrients, the heart is not necessary. At birth, respiration suddenly switches and the lack of a heart becomes fatal.
Sometimes acardius is combined with acephaly, as on the right.
In these cases, the only compassionate thing to do is let the pregnant woman have an abortion and recover from the failed pregnancy.