The Summer of the Ubume — Natsuhiko Kyogoku

In Japanese folklore, a ghost that arise from the burial of a pregnant woman is an" Ubume."
"The Summer of Ubume" is the first of Japan's hugely popular Kyogokudo series, which has 9 titles and 4 spinoffs thus far.
Akihiko "Kyogokudo" Chuzenji, the title's hero, is an exorcist with a twist: he doesn't blieve in ghosts. To circumnavigate his clients' inability to come to grips with a problem being their own, he creates fake supernatural explanations--ghosts--that he the "exorcises" by way of staged rituals. His patients' belief that he has vanquished the ghost creating their problems cures them.
In this first adventure, Kyogokudo, must unravel the mystery of a woman who has been pregnant for 20 months and find her husband, who disappeared two months into the pregnancy. And unravel he does, in the book's final disturbing scene.