A mother's joy at giving birth to her healthy baby boy last week turned into a nightmare, after the newborn was mistaken for another and surgery was performed on him.

Ms Jennifer Melton broke down in hysterics when a nurse told her that a frenulectomy had been done on her son, Nate, at the University Medical Center in Lebanon, Tennessee, following what she thought had been a routine check-up.

Frenulectomy is a procedure where the flap of skin tissue that connects the tongue to the floor of the mouth is cut.

It is required when the flap of skin is too tight, which could lead to future eating and speech problems. CNN reported that about 5 per cent of all babies have some form of tongue-tie that could also cause breast-feeding complications.

According to news channel WTVF, the doctor who performed the surgery had somehow gone ahead without obtaining the mandatory signed consent from the baby's parents.

"Essentially they took our child who was healthy from the room and cut his mouth," said Ms Melton. "At that point I began to cry hysterically."

The doctor, who was not named, admitted in a hospital progress report that he had "asked for the wrong infant" and apologised for the mistake.

But the apology provided scant consolation to Ms Melton. Her attorney, Mr Clint Kelly, said: "It's recklessness. There's no excuse for cutting on a healthy child. There's no excuse for mixing up babies at a hospital.

"We don't know if the child will have speech problems or eating problems. The concern here is this was a healthy baby that was supposed to leave the hospital, but instead was harmed by the hospital."

University Medical Center declined to comment on the incident, citing federal privacy regulations.