But after suffering the heartbreaking loss of her premature son two years ago, she has defied the odds and given birth to live twins while undergoing kidney dialysis, in what is believed to be the first case in the world.
The Rotherham mum has had kidney disease for more than a decade, and usually requires dialysis three times a week.
But during her pregnancy, doctors put her on the treatment daily.
Women with kidney failure are often advised against becoming pregnant because of the high rate of complications for the mother and developing baby. Many women on dialysis also have anaemia and hormone changes.
Two years ago, Miss Pearce’s son Karter was born three months premature, and weighed just more than a pound. He died after just four weeks.
The risk of a similar tragedy was deemed so high that the 29-year-old was given the option of an abortion.
She said: “I said no because I don’t believe in it, so they kept a close eye on me this time in case anything went wrong.”
Miss Pearce, from Rawmarsh, was determined to become a mum and Henley and Harper arrived last month, 12 weeks early.
She underwent an emergency Caesarean section with Henley weighing 2lb 1oz and his sister just 1lb 14oz.
Both babies are now in a special care unit where they will remain until they have reached their full 40-week term after being born at Sheffield’s Jessop maternity wing last month.
A week before the Caesarean, a scan showed Henley was not getting enough blood flow to his umbilical cord.
Miss Pearce said: “I was scared it was happening again, but Harper helped a lot I believe - she helped Henley through it and told him to carry on because she is the stronger one.
“At the Jessop’s they couldn’t believe it was a normal conception - they’d never seen anyone like me before.”
The twins have been moved from Sheffield to Rotherham Hospital, where their mum can easily visit them after her dialysis sessions.
“Henley has been on a ventilator and Harper is fine, she just needs to put more weight on,” she said.
“They’ll be in the unit until they’re full term. I can’t wait until they can finally come home.”
Miss Pearce was diagnosed with incurable kidney scarring, which affects her organs’ ability to filter waste from the blood, when she was just six weeks old.
The disease left her tired and lacking energy and she was placed on the transplant list for a replacement kidney.
A match was found and she was given a transplant aged 12.
But three-and-a-half years later medics discovered her body was rejecting the organ, and she began twrice-weekly dialysis. Doctors told her she would never conceive because of the effects of her treatment on her body.
Miss Pearce said: “I was shocked at first when I found out I was pregnant, but I’m so happy they are here and well.
“It’s unbelievable. It’s all I’ve ever wanted to be a mum.”