Ms Thomson, who lives in Maryhill Tce, Mornington, knew when she was called out at 10pm she would not be able to drive to Dunedin Hospital's Queen Mary Maternity Annex.
She called a taxi and had waited on the footpath for 40 minutes before gratefully accepting the driver's offer of a ride to Dunedin Hospital.
He even delivered her to the hospital door, she said yesterday.
"Once we got to the flat, I said I was happy to walk, but he took me the whole way. I am very grateful to him for his kindness."
Mother-to-be Rebecca Cocker was relieved when Ms Thomson arrived about 11.30pm.
"I was terrified she wasn't going to make it."
But it turned out there was plenty of time. Daughter Bella arrived at 4.49am, with Ms Thomson and proud father Andre Clarke close by.
Bella, weighing in at a healthy 3.94kg (8lb 11oz), is a sister for 6-year-old Flynn Cocker.
Ms Thomson made it almost all the way home by taxi about 8am yesterday.
"I got them to drop me off at the top of Maryhill Tce - the part of the street I live on was too steep to risk - and walked and slid down the rest of the way."
A midwife for 25 years, Ms Thomson said she had supervised births in unusual circumstances before, probably the most memorable being in refugee camps for Vietnamese boat people in Malaysia and Hong Kong.
"But the weather was better there," she said.
