As Liana Gedz was wheeled into an operating room at Beth Israel Hospital in September, she had every reason to trust Dr. Allan Zarkin in delivering her first child.

He had coached her through seven months of prenatal care, and the two had developed a friendship that one lawyer described as ''more than a doctor-patient relationship.'' It was the kind of bond that led Dr. Gedz, a dentist, to invite Dr. Zarkin, 61, to spend summer nights with her and her husband at their country home in East Northport, on Long Island.

But on Sept. 8, the day after undergoing a Caesarean section that delivered a healthy girl, Dr. Gedz held a mirror up to her stomach in a recovery room and discovered that Dr. Zarkin had carved his initials, A. Z., into her abdomen.

''I feel like a branded animal,'' Dr. Gedz said at a news conference yesterday after The Daily News reported the incident. ''It was supposed to be one of the most exciting times in my life, but it was a nightmare.''