Charlene Wells and Eamon Parkes found out she was pregnant on the same day she gave birth to their son Carlo Parkes-Wells.

Most expecting parents have nine months to prepare themselves, but for one Nelson couple, a life-changing surprise happened literally overnight.

Charlene Wells, 28, and Eamon Parkes, 31, had no idea Wells was pregnant when her severe abdominal pain was revealed to be the onset of labour.

"I was pretty shocked. I thought it was kidney stones or something," Wells said.

Marion van Dijk "Most people have eight or nine months to prepare. We had about nine hours."

She arrived at Nelson Hospital about 9am on Thursday morning where she was quickly told by staff that she was 40 weeks pregnant and due to deliver.

Following a 12-hour labour, Carlo Leslie Parkes-Wells arrived at 11.55pm, weighing a healthy 7.9 pounds (3.58 kilograms).

Wells had no idea she was pregnant. She had experienced some lower back pain but attributed it to long hours on her feet at her job as a sous chef at Stoke's Turf Hotel.

MARION VAN DIJK Eamon Parkes said the surprise birth had been "the talk of the town".

Because her placenta had been resting at the front of her stomach, Wells never felt any kicking or movement.

"[Hospital staff] were trying to rule it out at first. I normally bike a lot so I thought I had just put on a couple of pounds from a sleepy winter," she said.

Parkes said the surprise birth had been "the talk of the town".

"They say it's more common than you think, but it's not common for Nelson. It's one of those stories you read from overseas.

"You're trying to get your head around your normal everyday life and then this little man enters the mix.

"Most people have eight or nine months to prepare. We had about nine hours."

The birth has hugely altered the lives of the couple who will live solely off Parkes' income as a Pak'nSave baker for the next three months as Wells settles baby Carlo into a routine.

They have the added pressure of needing to move out of their current Exeter St home in three weeks time when it is sold by the owner.

Friend Janaya Te Tomo posted a plea for help on Facebook and said she was astounded by the generosity of around 30 Nelsonians who donated goods.

"There are people out there who don't have children but say 'I'll buy a pack of nappies'.

"We have got everything from prams, to nappies and clothes. You name it, we've got it. Some of the stuff is still brand new with tags on," Te Tomo said.

The couple said the support from the wider community alone, as well as from friends and family has been incredible.

Friend Richard Lee found out about the surprise pregnancy from Parkes on Thursday afternoon.

"He calls me and goes 'are you sitting down?' and I said yes, and then he spent five minutes taking the piss, and then he said Char was in labour," Lee said.

"Eamon's never been one to say 'I want a family', but he was like 'mate, I'm over the moon'."

Wells and Parkes had been together for nine years, but had not considered having children.

With Christmas fast approaching, Parkes said Carlo's birth was "the best present I could ever ask for".

The family is hoping to relocate to Richmond when their tenancy expires.