Leanne Allen, 37, gave birth to surprise baby Harley at 31 weeks despite suffering a miscarriage months earlier and her husband having a vasectomy.
After suffering months of renal problems, tiredness, high blood pressure and swollen legs doctors called her in for an MRI scan.
The astonished now mum-of-three was baffled when doctors announced they had “found something she needed to talk about” - a perfectly healthy fetus.
Worried she had potentially-fatal condition pre-eclampsia, they booked her in for an emergency c-section and she was born 30 hours later.
Leanne - who was on a hen do the week before - didn’t even have time to tell kids Jayme, 14 and Mitchell, 12, before Harley was born.
They recorded their son and daughter’s reaction when they revealed the surprise 3lb 8oz arrival in a heartwarming video.
Leanne and and hubby Kevin, 35, said the premature tot is a “true miracle” and are frantically adapting their home and life to welcome her home.
Shocked Leanne, from Gosport, South Hampshire, said: “During my renal scan my kidneys were checked along with my bladder but then the lady started asking questions that felt irrelevant.
“She then said she had found something on the scan that she needed to tell me.
“Straight away I was panicked, thinking she had found a tumour.
“When she then told me I was pregnant I nearly fell off the bed.
“And when she went on to say I was 31 weeks I just went into shock.
“She briefly showed me baby on the screen and got me some water.
“30 hours later I was being prepared for surgery and I had a baby daughter.
“Touching her tiny head that first time was so amazing, I loved her so much already - despite only knowing she even existed for two days!”
Store manager Kevin added: “We literally went from kidney scan, to being pregnant, to having a baby in 30 hours. I still can’t believe I’m a new dad again.”
Housewife Leanne suffered a miscarriage in January and not wanting to extend their family, it prompted Kevin to have a vasectomy.
It is now thought this was a second baby - Harley’s non identical twin - and miraculously their daughter hung on to survive.
After flying home from a hen do in Barcelona in early June - where she unknowingly enjoyed a few rums - she started experiencing a lot of pain and fluid retention.
Having suffered with health problems for years, she knew it was a sign of dangerously high blood pressure and kidney problems, and was booked in for a scan.
Shocked Leanne broke the pregnancy news to Kevin on the phone who rushed to Queen Alexandra Hospital in Portsmouth - to be by her side last Wednesday (5th).
Medics spent the next day trying and failing to bring down her dangerously high blood pressure, before deciding to perform a c-section on Friday (7th).
Baby Harley was whisked straight to NICU and after a quick visit Kevin rushed home to get the kids - who were staying with friends and had no idea their mum was pregnant.
They broke the news on camera, telling them they wanted to show them “what had been making mum ill” - before revealing a photo of Harley.
Kevin explained: “It was all so much of a shock and happened so fast that we didn’t want to tell anyone until we knew she was fine.”
Doctors now believe Leanne’s kidney, blood pressure and swelling problems were caused by a combination of her pregnancy and pre-eclampsia.
It is hoped Harley, who is still in intensive care due to her premature arrival, will be home in a few weeks time.
Leanne added: “When I was finally able to go and meet my little girl I was shocked at just how little she was.
“The following days were tough, being on separate wards and only being able to touch her in the incubator.
“But she was doing so well that she no longer needed oxygen and began having small amounts of milk via her tube.
“On day four she had her lines removed and that meant I could finally have my first cuddle.
“She was tucked inside my night dress and just snuggled into my chest. She stayed like that for an hour, both of us completely content.
“Harley seems to be making good progress and hopefully there will be no long term affects from me not knowing I was pregnant or from her early arrival in to the world.”
Kevin has been frantically buying and borrowing everything from cribs and car seats to nappies and bibs for the unexpected new family member.
“It’s just absolutely mind boggling to think that a week ago how different our lives were,” said Kevin.
“It has been a whirlwind of emotions.
“Harley is an absolute miracle.
“Of course I had the snip and we never intended to add to our family, but the second we saw her out hearts melted and we fell totally in love.”