At birth, Melinda Star Guido tipped the scales at only nine-and-a-half ounces (270 grams) - making her one of the world's smallest babies.
Most infants her size wouldn't have survived, but doctors at Los Angeles County-USC Medical Centre have been preparing to send her home by New Year's Day.
Melinda was born premature at 24 weeks in August, and spent her early months cocooned in an incubator at the hospital's neonatal intensive care unit.
Almost every day, her 22-year-old mother Haydee Ibarra has sat by her bedside, and she stays overnight whenever she can.
Melinda is believed to be the second-smallest baby to survive in the US - and third in the world.
"It's a big, huge miracle," Ibarra said the day before her original due date. "She's been through a lot and she has made it. A lot of people doubted her."
"This is our star baby here," said Rangasamy Ramanathan, a doctor at the neonatal intensive care unit. "Now the baby weighs eight times what the baby weighs when it was born."
Ibarra has often been restricted to caressing Melinda through the portholes of an incubator and doctors continued tests this week to monitor her health.
"They thought she wasn't going to make it," said Ibarra, explaining that if Melinda had been younger than 24 weeks, the doctors may not have been able to save her.
"If she wasn't 24 weeks they wouldn't even have bothered trying," she added.
During her pregnancy, Ibarra suffered from high blood pressure, which can be dangerous for both mother and child.
At 24 weeks, she was transferred from a hospital near San Fernando Valley to Los Angeles County-USC Medical Centre, which is better equipped to handle high-risk pregnancies.
Tests confirmed that there was a problem with the placenta, the organ that connects to the developing foetus.
The foetus was not getting proper nutrition, blood and oxygen.
Doctors told Ibarra and her husband Yovani Guido that, even if their baby survived, children born so premature can have developmental delays and impairments such as blindness, deafness or cerebral palsy.
The couple said they would take the chance - and Melinda's progress has surprised both staff and relatives.
Melinda was delivered by caesarean section and immediately transferred to the neonatal intensive care unit, where a team of doctors and nurses kept watch around the clock.
"We have had babies at 23 weeks, but 24 weeks and weighing 270 grams - that's a miracle for us," said Ramanathan. "You're talking about one to two percent. (A) 99 percent chance we'd have lost the baby."
"She's a little miracle to me," agreed Ibarra.
APTN