Eating of newborn kittens appears to be associated with a large litter, the second pregnancy, highly nervous first-time cats, and illness in kittens.
Other situations can provoke cannibalism such as stress caused by the queen unable to find an appropriate nesting area, or if the queen is extremely malnourished. Hormonal triggers can also induce cannibalism, where the maternal effects of prolactin are overridden by instinctual drives to prey-kill.
Evisceration and ingestion of newborn kittens while chewing the umbilical cord too closely are not true cannibalism, and although this also occurs, especially with inexperienced and nervous cats, it is rare and related to hypervigilence by the queen post-queening.
Progestins, such as megestrol acetate, have been reported as effective against such behaviour in queens.