Doctors were shocked after discovering that a woman was five-weeks pregnant - just after they'd put her under general anaesthetic and were preparing to perform keyhole surgery to discover why she couldn't conceive.

Tia Reed, a 19-year-old from Birmingham, was diagnosed with endometriosis in August 2017 having suffered from painful periods throughout her adolescence and thought she was infertile.

When someone has endometriosis, cells similar to the ones found in the lining of the uterus also appear in other places around the body, breaking down and bleeding on a monthly basis.

Ms Reed feared that the debilitating condition had caused her to become infertile, as she’d been unable to fall pregnant with her partner, 22-year-old Liam Twining, despite having a very active sex life.

She was booked in to have a laparoscopy, a form of keyhole surgery that allows the surgeon to have a look at the inside of the abdomen without making a large incision.

Having had her general anaesthetic administered, Ms Reed was lying on the operating table waiting for the surgery to begin when the procedure was interrupted.

A urine test that Ms Reed had taken before the operation had revealed that she was five weeks pregnant with her first child, meaning that she didn’t have to go through with the procedure after all.

Tia Reed and Liam Twining (SWNS)

Ms Reed became unconscious under the influence of the anaesthetic, waking up a few hours later unaware of the surprising discovery.

“I woke up completely delusional after what felt like seconds,” she said.

“I remember asking the anaesthetist if it was all done and he replied ‘we will explain later’.”

The dental assistant then dozed off for a few more hours. When she woke up, she couldn’t understand why there were no bandages on her stomach.

“At this point I started to freak out and thought: ‘How the hell have they gone in to perform it?!” she said.

When the anaesthetist came into the room, he informed Ms Reed that they’d been unable to perform the surgery, which caused her to fret.

“I started to panic. I just thought the worst and thought they had come across something,” she said.

Ronnie James Twining was born on May 23 2018 (SWNS)

“Then he said: ‘The good news is you’re pregnant’.”

Ms Reed and Mr Twining’s son Ronnie James Twining was born via caesarean on May 23 weighing 8lb and 8oz.

Despite enduring four days of tough labour, Ronnie James is reportedly in very good health.

Ms Reed fears that her endometriosis will come back in the near future.

Before the birth of her son, the condition had been so painful after sex that doctors had prescribed her zapain, which is a mix of paracetamol and codeine.

“Since I’ve had Ronnie I am very worried about the endometriosis making a return, I get anxiety when I think about the pain I could soon be in,” she said.