Ubume (産女) are Japanese yōkai of pregnant women who has died during childbirth. Passersby will see her as a normal looking woman carrying a baby. She will typically try to give the passerby her child then disappear. When the person goes to look at the child in their arms, they discover it is only a bundle of leaves or large rock. The idea that pregnant women who die and get buried become "ubume" has existed since ancient times; which is why it has been said that when a pregnant woman dies prepartum, one ought to cut the fetus out the abdomen and put it on the mother in a hug as they are buried. In some regions, if the fetus cannot be cut out, a doll would be put beside her.

Gantz