The doctor at a hospital in Fukushima, 150 miles north of Tokyo, had been accused of cutting off the placenta attached to the woman's uterus without taking risk-aversion measures, Kyodo news service reported.

A firm attachment of the placenta to the uterine wall is a rare condition, known as placenta accrete, the report said.

Prosecutors in the 2004 case had argued the doctor was aware the detachment could cause bleeding.

The doctor's lawyers claimed he had tried all possible medical procedures to save the woman's life. They said there was no bleeding in the beginning and that what happened subsequently couldn't have been anticipated.

Medical circles in Japan were upset over the doctor's indictment, calling it an intervention in medical procedures, Kyodo reported.

The Japan Association of Obstetricians and Gynecologists welcomed the ruling, calling it "a rational decision."

The incident has been blamed as contributing to the growing shortage of obstetricians in the country.