Dancer Jodie Smith, 17, of Carleton Glen, Pontefract was taken to Pontefract A&E in the early hours of last Tuesday.
Hours late Jodie gave birth to 8lb baby boy son Jack Arthur.
Jodie’s mum Lesley, 47, said: “We are still a bit shellshocked. Jodie hasn’t stopped smiling, like ‘I can’t believe I’ve had a baby’.”
She added Jodie hadn’t put on any weight and was completely unaware she was pregnant .
Lesley said: “She has been going to college, going to work, doing her dance classes, going to the gym, all as normal. She wasn’t ill and looked just as slim all the way through.”
Jodie is still planning to go to college to study dance.
Her boyfriend, Danny Yeoman, 19, said: “It’s been a shock, we’re still getting used to it.”