A doctor in the United States decapitated a woman’s baby during a “nightmare” delivery, a legal case has claimed.

Dr Tracey St Julian is being sued for gross negligence by Ms Jessica Ross and Mr Treveon Taylor, whose son died at Southern Regional Hospital in Georgia during a complicated birth.

Their lawyers claimed Dr St Julian had been too forceful with the baby during the delivery.

Several nurses are also being sued for concealing the incident, the BBC reported.

Mr Cory Lynch, one of the lawyers in the legal team, said the couple were “so excited about the birth of their first child”.

“Unfortunately, their dreams and hopes turned into a nightmare that was covered up by Southern Regional Medical Centre,” he said.

The Medical Examiner’s Office and Clayton County Police are investigating the case, which they were made aware of on July 13, though the death occurred on July 9.

According to the attorney’s statement, Dr St Julian attempted to deliver the baby vaginally using different methods, including “applying traction to the baby’s head”.

Lawyer Roderick Edmond, also representing the parents and who is also a doctor, alleged that Dr St Julian had applied “ridiculously excessive force” to the baby.

“Dr St Julian came in, and she, in the process of trying to deliver the baby, pulled on the baby’s head and neck so hard, and manipulated them so hard, that the bones of the baby’s skull, face and neck were broken.”

The baby was not able to be delivered vaginally owing to shoulder dystocia – which happens when the baby’s shoulders become stuck in the birth canal.

Dr St Julian, a board-certified obstetrician and gynaecologist, did not proceed with a caesarean delivery at the appropriate time, as previously requested by the couple, the lawsuit says.

Ms Ross and Mr Taylor, both 21, attended a news conference on Wednesday in Atlanta where their lawyers announced the suit against Dr St Julian and Southern Regional Medical Centre, a hospital in Riverdale.

Mr Lynch alleged in graphic detail the measures staff had taken to cover up the horrific incident, including wrapping the baby’s body in a blanket and propping his head up to make it look like it was still attached.

He claimed that medical staff had failed to report the incident.

The couple found out what had happened to their son only while making arrangements at the crematorium, four days after his death, according to the lawsuit.

Prime Healthcare Services, which owns the hospital, said its “heartfelt thoughts and prayers are with the family and all those impacted by this tragic event,” BBC reported.

“Our commitment is to provide compassionate, quality care to every single patient, and this loss is heartbreaking,” the hospital said.

It added that Dr St Julian was not an employee of the hospital, and it had “taken the appropriate steps in response to this unfortunate situation”.

The suit alleges gross negligence, fraud and intentional infliction of emotional distress. It seeks unspecified compensatory damages, in addition to covering the cost of the infant’s US$10,000 (S$13,500) funeral.

Dr St Julian has not yet filed her defence and has not issued a public comment on the case.