Nandini, 19, who goes only by her first name, gave birth to her first child by caesarean section on Monday 23 May 2016, in Hassan, India.
Doctors believe the baby's weight overtakes the current record holder, Carisa Rusack, who was born weighing 14lb 5oz in Massachusetts in 2014.
Dr Venkatesh Raju, the local health officer, said: "In my 25 years of experience, I had never seen such a big baby. She is a miracle.
"I believe she is not only the heaviest baby born in India, but the heaviest baby girl ever born in the world."
The yet-to-be named baby girl reportedly left her mother and medics "in shock" due her size.
Nandini, who weighs 94 kg and stands 5'9 tall, had a smooth pregnancy and was unaware she was going to give birth to a big baby.
While the mother's size hinted at high sugar levels, doctors confirmed that she is not diabetic, which has been linked to obesity in newborn infants.
The baby is being kept at the neonatal intensive care unit and doctors are monitoring her developments. They hope to discharge her in a few days.
Dr Poornima Manu, the gynaecologist who delivered the baby said: "She came as a big surprise for all of us.
"The surgery took place for nearly half an hour and it was free of any risk. She is really big and beautiful.
"She does not have any health issues like irregular sugar levels or thyroid and is breathing well. We were initially concerned about her sugar levels but that is normal.
"The mother had made regular visits for check-ups at the hospital and never showed signs of gestational diabetes or thyroid disorders.
"Both the mother and the child are doing fine and we will discharge them once we are confident of the baby's health."
Nandini and her husband Arun married two years ago and were excited about welcoming their first child. Now that she is here, they said they are "overjoyed" to be parents and are counting down the days when they can bring her home.