Police say the baby was found at about 5:40 a.m. Tuesday by a resident who discovered the infant in a car seat at the end of a neighbour's driveway.
Paramedics and police were called and the infant was taken to hospital.
Police say officers checked the home to see if any other children were at risk and found the baby's father — who they say had been sleeping — inside.
They say the man was bound by a probation order not to attend the address and they allege he had been drinking alcohol — also a violation of the order.
Police say an investigation found the baby's mother had been arrested just before 2 a.m. for driving while impaired by drugs.
It's not known exactly how long the baby was left in the driveway but investigators believe the child was placed there before the woman drove away earlier that morning.
The baby has been turned over to the care of the Children's Aid Society after being checked medically.
A 31-year-old London woman has been charged with failing to provide the necessaries of life and abandoning a child and is to appear in court April 9.
A 31-year-old St. Thomas man is charged with two counts of breach of probation and is to appear in court April 1.
Note to readers: This is a corrected story. A previous version stated the woman was due in court on April 1.