Jo Hambry, 35, from Plymouth, went into labour nine weeks early after seeing husband Adam, 32, fighting for his life.
Jo went into labour while with Adam in intensive care. She was whisked away to the maternity ward, where she gave birth to baby Grace, weighing 4lb, 6oz.
Adam, a fisherman, was returning from work with friends when he collided with another car. He shattered his right leg, damaged a finger, ripped muscles in his neck and fractured his hip.
In a series of four operations at Derriford Hospital, Plymouth, surgeons fitted metal pins to re-attach 20 pieces of bone, stitching Adam's leg back together with dozens of thick staples.
"They said there was a 25 per cent chance of losing the limb," he said. "I accepted I was going to lose it to be honest - I was just happy to be alive. It's going to be six months before I can walk again and they've said I probably won't ever walk straight again.
When she was told about the crash, mum-to-be Jo rushed to the hospital, but the shock of seeing Adam after the accident triggered labour nine weeks early.
Determined to be by Jo's side, Adam asked nurses to wheel him down to the maternity ward to see Grace's arrival by Caesarean.
"The nurses rushed me into the lift and got me to the maternity ward," Adam told his local paper. "A couple of Naval nurses got me down there like a bat out of hell.
"I was in the delivery room on one bed and Jo was on the bed next to me. It was amazing what they did for us; it's never happened before, apparently.
"We're convinced it was the stress of the crash that brought on the contractions. As soon as the baby arrived I just forgot about everything. She's amazing. We couldn't have asked for a healthier baby. She's just beautiful."
Grace is still on a drip in intensive care but is perfectly healthy.
Jo, who wasn't due to give birth until early next year, is recovering in hospital and is confined to a wheelchair.
"I'm the luckiest person alive at the moment," she said. "I thank my lucky stars every day. It could have been a totally different Christmas."
Devon and Cornwall Police said its Serious Collisions Investigations Unit is working to establish the circumstances leading up to the crash.
Anyone with information should call the police on 101 quoting log number 653 of November 17.