When a 24-year-old mother went to the doctor's office because of a terrible backache, she thought she had developed a kidney infection. However, just six hours later, she was giving birth in the hospital.

Kayleigh Renwick, a childcare nurse from the UK, knew nothing of her pregnancy and within minutes after seeing a doctor, the unsuspecting mother was rushed to the hospital to give birth to a baby who was already five weeks overdue.

Renwick, who is now a mother of two after giving birth to a 7lb 7oz daughter, said she did not realize she was pregnant because throughout her pregnancy she continued to have periods and that she was rapidly losing weight.

"You read about women not realizing they were pregnant and think 'how did you not know?'. I had no pram, no cot, nothing. I'd given it all away after Grace as was adamant we weren't going to have another baby," she said, according to ChronicleLive.co.uk.

Renwick, who is the mother of two-year-old Grace and newborn Lucy, said that she started feeling the agonizing back pains when she was in the park with her family in May.

She had initially thought her pains were caused by a kidney infection and visited an out-of-hours medical clinic for medication.

However, while she was waiting for the results of a routine urine test, the doctors came out and asked her how far along she was in her pregnancy.

Renwick had insisted that she wasn't pregnant, and the doctors sent her to the hospital for a scan.

"Just after 6pm I was seeing a doctor and by 7.30pm I was at the maternity ward having a scan," she said. "If they'd said I was four months pregnant I could have got my head around that but they said 'It's good news, there's a baby there and you're 8cm dilated.'"

"I couldn't believe it. My body went into shock and I started throwing up," she said. "I had periods throughout the pregnancy and in February was sick a couple of times so did a pregnancy test and it came back negative. There were just no further symptoms," she explained.

Lucy was born weighing 7lb 7oz with very dry and cracked skin. The midwives had told Renwick that it was because her placenta had stopped working.

"They didn't know what Lucy had been surviving on and thought she was up to five weeks overdue," she said. "She was back-to-back and they think tucked behind my pelvis which is why I was getting the back ache. Grace has been brilliant with Lucy, it's like she's always been here."

Little Lucy, now half-a-year-old, has been diagnosed with severe Brachycephaly and Plagiocephaly, commonly known as Flat Head Syndrome. Brachycephaly refers to flatness at the back of the head and Plagiocephaly refers to flatness at the sides of the head.

While both conditions can cause changes to a baby's facial features, like unevenly aligned ears and eyes and jutting forehead, the condition is generally classified as a cosmetic problem.

The condition is usually caused by a baby's sleeping position or other factors in the womb like lack of amniotic fluid and the position of the baby. Flat Head syndrome occurs when a baby's soft skull bones are subjected to abnormal or prolonged pressure.

Lucy will now need a cranial helmet to re-shape her head. She will have to wear the helmet 23 hours a day with the possibility of developing blisters on her head in the first seven weeks of treatment.