A teenager didn't know she was having a baby until she was in labour because she hadn't shown any signs of pregnancy.

Charlotte Thomson, now 21, of Newcastle upon Tyne, had regular periods and was still slipping into her size 8 dresses so had no idea she was expecting.

It wasn't until she took herself to hospital with bleeding and painful stomach cramps that medics told her she was about to give birth.

Daughter Molly, now two, arrived two hours later.

Seven months pregnant: Charlotte Thomson, now 21, still slipped into her size 8 dresses and continued to drink alcohol throughout her pregnancy, not realising she was expecting

Today: The proud mother-of-one with daughter Molly, who was born in December 2015

Nursery nurse Charlotte said: 'My stomach was completely flat, and I'd been having regular periods so it was such a shock when I found out.

'I didn't believe that I was actually pregnant until I gave birth. 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.'

Some women experience period-like vaginal bleeding during pregnancy that can have a number of different causes including cervical changes, vaginal infections and when the embryo first implants itself in the wall of your womb.

Charlotte, who fell pregnant with an ex-boyfriend, said she only put on 3lbs during her pregnancy and had felt more tired than usual but put the symptoms down to her party girl lifestyle.

'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.'

No bump: A slender Charlotte, then 19, at two (left) and three months pregnant (right)

Four months pregnant: Charlotte with her mother Lynne, who supported her daughter when she was told she was in labour in hospital

In December 2015 Charlotte woke in agony at 2.30am and realised she was bleeding profusly.

She said: 'I took some paracetamol and hoped that it would blow over.

'Instead, the pain just got worse and I was in agony. An hour later I felt like I was going to be sick so I ran to the toilet and saw that my underwear was full of blood.

'I had just finished my period so I was really scared. I knew something was seriously wrong and booked a taxi to the hospital.'

Not showing: Charlotte at six (left) and eight months pregnant (right). The teenager only put on 3lbs during the pregnancy

Nurses at Northumbria Specialist Emergency Care Hospital examined Charlotte and told her she needed to speak to a midwife.

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

But ten minutes later, a midwife performed an ultrasound and told Charlotte she was nine months pregnant and in labour.

Charlotte continued: 'I panicked that I wasn't prepared and hadn't bought any baby clothes. I was so worried about what my parents would say when they found out that I was having a baby.'

Surprise arrival: Charlotte welcomed baby Molly just three hours after discovering she was pregnant

Instant bond: Charlotte said she loved Molly, pictured in hospital, as soon as she held her

At 4.30am, a nurse phoned Charlotte's parents, Lynne Thomson, 50, a domestic cleaner, and Vincent Thomson, 50, an engineer, and told them their daughter was pregnant.

Charlotte said: 'My parents thought that I was only a few weeks along and having a miscarriage.

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

Two hours later, Charlotte gave birth to Molly.

Charlotte said: 'As soon as I held Molly, I loved her so much. She was perfect and we had an instant bond.'

Slender frame: Charlotte said she had little baby weight to lose because she had stayed so slim

Proud: Charlotte said she can't wait to tell Molly, pictured, the story of how she was born

Doctors explained that she'd had no bump because Molly had been tucked up underneath her ribs.

Charlotte said: 'It's crazy to think that I'd been carrying a baby all that time.

'When Mum called my work to explain that I'd had a baby, they were gobsmacked as they'd seen me the day before with no baby bump at all.'

Charlotte and Molly were discharged from hospital two days later – after Lynne rushed out to buy nappies and baby clothes.

Charlotte says: 'My friends didn't believe me until they saw a picture of Molly. Luckily I'm still a size 8 and didn't need to lose any baby weight.

'Molly has joined the nursery that I work at so I can take her with me, which is perfect.

'Molly's dad is an ex who is no longer in the picture, but I have plenty of help from my parents with the baby. I'm no longer a party animal but it's worth it to have Molly.

'I can't wait to tell her the story of how I discovered I was pregnant with her. Nothing Molly could ever do in the future would surprise me as much as the day she was born.'