Fertility treatments helped Lisa Rea conceive even she had a gastric band fitted to lose weight.
The 37-year-old piled on the weight after she was diagnosed at the age of 18 with polycystic ovaries, a condition that affects fertility.
At 26 stone, tax clerk Lisa, of Worsley, near Manchester, tried for years to have a baby.
Lisa was so overweight the little girl would shelter from the rain under her mum's 44JJ bust.
Then four years ago tax clerk Lisa, of Worsley, near Manchester, had the drastic slimming operation.
The band round her stomach meant she could only eat and drink minute amounts, and doctors told her that the tiny amounts of food Lisa had to eat would not be enough to nourish a baby in the womb.
However, after losing a whopping 16 stone, Lisa is now a mum to a boy.
"I really thought I would never see this day, it is unbelievable," News of the World quoted Lisa as saying.
"The gastric bypass was the best fertility treatment I could have hoped for - I got pregnant within weeks," she added