So, when Tripp celebrated his first birthday, he was appropriately dressed in a Superman outfit.
"We're amazed by him," Tripp's mom, Trashinda Gavin of Mobile, Alabama, told "Good Morning America." "Our baby that was not going to survive is celebrating a 1-year birthday."
Gavin was just five months pregnant with Tripp, her second biological child, when she went into preterm labor.
She was hospitalized for several days at USA Health Children's and Women's Hospital in Mobile, where she said she and her medical team worked to delay labor for as long as possible.
But on July 12, 2023, just 21 weeks and three days into her pregnancy, Gavin gave birth to Tripp, who weighed just 15.3 ounces at birth.
"I remember his arms and legs moving and asking, 'Is he OK?' and [my husband] saying that he was OK," Gavin recalled. "I told them I wanted them to do anything they could to save the baby."
Babies born prior to 22 weeks are born without their critical organs fully developed, including their heart, lungs and intestines, according to Dr. Maran Ramani, chief of the Division of Neonatology at USA Health and the doctor who oversaw Tripp's care.
Ramani and Lisa Gore, a neonatal nurse practitioner at USA Health Children's & Women's Hospital, told "GMA" that even as a hospital that specializes in neonatology, over the past decade, they have only cared for around 10 babies born before 22 weeks, and only half of those babies survived.
"Tripp's case is unusual," Gore said. "There still are not a lot of cases of babies less than 22 weeks surviving ... Our OB team works really hard at trying to keep these moms pregnant as long as possible, because every single day matters."
Once Tripp was born, he was immediately put on a ventilator and taken to the hospital's neonatal intensive care unit, according to Gore and Ramani.
In the NICU, Gavin and her husband, Herron Abney II, had to wait one month to even hold their son because he was so small and under so much medical intervention.
According to Gore and Ramani, babies born before 22 weeks are often so small they fit in the palm of an adult's hand. Their eyes are usually closed and their footprint is close to 1-inch long.
"It was scary to look at him, he was so small," Abney said, describing it as surreal to watch Tripp grow outside the womb and observe what normally happens in the last months of pregnancy. "I had faith, but I wasn't sure he would survive."
Both Gavin and Abney also described it as "heartbreaking" to have to leave the hospital each night and say goodbye to Tripp.
The couple, already parents to a combined four children, said they balanced their work and school schedules -- Gavin is in nursing school -- to be able to visit Tripp multiple times a day.
"We never missed a day," said Gavin. "Especially once we got to hold him, I wanted to hold him so much."
Medically, Gore said Tripp experienced relatively few complications during his time in the NICU, a miracle for a baby born as early as he was.
"He actually had a pretty good course, particularly for somebody born as early as he was," Gore said. "But it's still very complicated because we have to grow them outside in an environment that they shouldn't naturally be in. They shouldn't be touched and they shouldn't hear the sounds and they shouldn't have all of these things that have to be done to them, so it's a long course and it's difficult."
Tripp spent the first five months of his life in the NICU before he was finally discharged in December, just before Christmas.
He weighed just 5 pounds at discharge, but came home with no ongoing medical issues, according to Gavin.
"It's a dream come true to know that our baby is home with us," she said. "We love having him home."
In July, Tripp celebrated his first birthday.
Abney and Gavin described their son as a "perfect little baby boy" who is learning to crawl and who demands his mom and dad's full-time attention.
"The day we left the hospital, a doctor told me, 'Tripp proved us wrong,'" Abney said, later adding, "You see what we have today."