A young woman has revealed how she had a baby despite not realising she was pregnant.

Charlotte Thomson, now 21, was 19 when she went into labour - but she’d had regular periods throughout her pregnancy and had also managed to wear her size eight clothes for all nine months.

The teenager from Newcastle upon Tyne had no idea she was pregnant so had been regularly partying with all her friends as usual, and she only gained three pounds over the whole pregnancy.

This is despite the fact that she gave birth to a seven-pound baby, Molly, who is now two years old.

Doctors explained that the reason Thomson’s stomach remained flat was because Molly was “tucked up inside” her ribs.

The nursery nurse says she felt a little bit tired towards the end of the pregnancy, but the teen merely put it down to too much partying.

“I thought it was from going out all the time,” she said. “I still managed to get into my clothes so I just ignored it.”

She had been having what she thought were regular periods too, but this turned out to be vaginal bleeding which can be caused by cervical changes or a vaginal infection.

Clueless man calls 999 for his wife in pain, seconds later she gives birth

It was only when Thomson went to hospital in the middle of the night complaining of stomach cramps and bleeding that doctors told her she was in fact nine months pregnant and in labour.

“I told them that there had to be a mistake,” Charlotte said. “I’d had no symptoms.”

Three hours later, Thomson gave birth to Molly.

Charlotte Thomson at six months pregnant (Hotspot Media)

“I didn’t believe that I was actually pregnant until I gave birth,” she says. “It was scary becoming a first-time mum with no warning. But I wouldn’t change Molly for the world, and I feel so lucky.”

Molly’s father is Thomson’s ex-boyfriend - the couple are no longer together, but the young mother says she has plenty of support from her own parents.

However Thomson was, unsurprisingly, nervous about what her parents would say when they found out she was about to have a baby.

“I burst into tears when they arrived, and told them I had no idea that I was pregnant,” Thomson said. “They were really supportive and excited about their first grandchild.”

After two days in hospital, Thomson and her newborn baby were discharged - fortunately Molly’s grandparents had been able to buy nappies and baby clothes in the meantime.

Molly now attends the nursery where her mother works, a situation which, Thomson says, is “perfect.”

She has, however, had to adapt her lifestyle.