Kiyoya Kawada, 61, an obstetrician at Kagawa Prefectural Central Hospital in Takamatsu, told Kyodo News that he implanted the three eggs -- two of which were the woman's -- on two occasions.

The woman was found to be pregnant in October by ultrasonic examination, but underwent an abortion because the hospital told her earlier that Kawada had implanted a fertilized egg believed to be from another patient.

"I was aware that (implanting more than one egg) would violate" the guidelines of the Japan Society of Obstetrics and Gynecology, Kawada said.

"But I did it to increase the pregnancy rate," he said.

Kawada's confession could spark a controversy as it allows for the possibility that the woman may have become pregnant with her own egg. There is also speculation that the hospital terminated her pregnancy without fully checking on the relationship between the woman and the embryo.

Kawada said he implanted two eggs in the woman on Sept. 18 and the third one on Sept. 20.