Hannah's mother, Linda, 28, from Blackwater, Hampshire, and her husband Andrew, 29, were knocked down while walking home from a birthday outing at the weekend.
Mrs Wolage was killed, but ambulancemen, realising she was pregnant, rushed her to Frimley Park Hospital where doctors carried out a Caesarian operation to deliver the baby on Sunday.
The couple had been to London Zoo on Saturday to celebrate Mr Wolage's 29th birthday and were just yards from their terraced home in Blackwater, when the accident occurred, hurling them into a garden.
The Fiesta car which hit them crashed into a lamp-post, trapping the driver, who had to be cut free but suffered only superficial injuries.
Neighbours dashed to help, but Mrs Wolage died immediately. Mr Wolage, a computer projects manager, suffered internal injuries and a number of broken bones. He was described as 'comfortable' in hospital yesterday.
His wife worked as a nurse at a nursing home in Sandhurst, Berkshire, before giving up work to have her baby, who was due on 15 September.
Saturday night's tragedy was reported to be the second to hit the couple in the past year.
Their first child, Alison, was born with three holes in her heart and died five months later at the Hospital for Sick Children in Great Ormond Street, central London, just days before Christmas.
The 47-year-old woman driver of the car involved in Saturday's accident has been bailed to report back to police while inquiries continue. A police spokesman said yesterday that the Crown Prosecution Service would now also have to consider the child's death.
'It will be a matter for the CPS to consider. It is a legally complex issue. The child was not born before the accident so can she be said to have died as a result of the accident?' the spokesman said.