Baby born with rare 4-pound tumor on her spine

When Kristin Tyler went in for a routine ultrasound 20 weeks into her second pregnancy , she said she was not prepared to learn her baby had a rare condition.

She said doctors discovered a fluid-filled mass at the bottom of the baby's spine, which was later diagnosed as a sacrococcygeal teratoma, a condition that occurs in 1 in 27,000 pregnancies, according to Texas Children's Hospital, where Kristin Tyler gave birth.

"Me and my husband were both very scared and very much in shock," the 23-year-old, who lives in Alexandria, Louisiana , told " Good Morning America ." "[My pregnancy] didn't feel any different than when I was pregnant the first time, so it was nerve-wracking."

She continued, "The best explanation that we got at the time was that there was a large mass connected to the bottom of her spine that was mostly filled with fluid."

A sacrococcygeal teratoma is a tumor that forms on the tailbone during fetal development, according to Texas Children's Hospital. The tumor can be life-threatening for the baby as it can cause complications ranging from preterm birth and bleeding to heart complications and dangerous swelling in the baby's body.

After receiving the surprise diagnosis, Kristin Tyler and her husband Jacob Tyler, who are also the parents of a 2-year-old son, traveled from their home in Louisiana to Houston to see a specialist at Texas Children's Hospital.

From that point on, Kristin Tyler said she made the nearly five-hour drive from her home in Louisiana to Houston every other week for prenatal visits.

In April, around 30 weeks into her pregnancy, Kristin Tyler said she moved to Houston along with her mom and her son William, because her pregnancy had to be so closely monitored.

Jacob Tyler stayed home in Louisiana to work his full-time job during the week and then drove to Houston to see his family on the weekends.

Through it all, the Tylers said they had no real assurance medically that their baby would survive past pregnancy or birth.

"The nature of the teratoma is that it was never known ... if she would make it to even come to term, to be be born, or if during the during the birth process, if she wouldn't make it. If anything ruptured, you know, she wouldn't make it," said Jacob Tyler. "They had a plan, but the plan only worked if everything went according to the plan. If not, there was a lot of things that could have went wrong."

As her due date approached, Kristin Tyler said her pregnancy became nearly as difficult physically as it was emotionally.

"It got to the point where it was very hard for me to even walk around," she said. "I had two amnioreductions because there was so much fluid. I couldn't sleep. I didn't want to eat. I felt sick all the time. Morning sickness got really bad even up until delivery."

On May 21, around one month before her due date, Kristin Tyler's doctors decided to induce her and delivery the baby via cesarean section.

Dr. Ahmed Nassr, the maternal fetal medicine specialist and fetal surgeon who oversaw Kristin Tyler's care at Texas Children’s Pavilion for Women, said when it comes to sacrococcygeal teratomas, doctors have to walk a fine line of deciding when to induce delivery.

"If we deliver the baby early, we expose the baby to prematurity, and also, if we wait and the heart function is deteriorating, the baby may develop heart failure and be born in a bad condition," Nassr told "GMA." "So it's usually a very fine balance, and that's why there is a lot of unknown."

Nassr led a team of nearly one dozen doctors in the delivery room who helped with the C-section, which had to be modified so as not to disturb the tumor, and provided neonatal care.

When the Tylers' baby, a daughter whom they named Adalida, was born, she weighed 10 pounds, 4 ounces, and carried a 4-pound tumor near her spine.

Nassr said Adalida's 4-pound tumor was one of the largest he's seen in his career.

Jacob Tyler said seeing his daughter outside of the womb brought both relief and additional concern.

"I was happy that she was born and I got to see her, and also, bluntly, I was like, 'Man, this tumor is really large,'" he said. "It was big."

Adding to the Tylers' concern was that Adalida was quickly taken to the neonatal intensive care unit, or NICU, where she was placed on oxygen to help her lungs develop and placed on a feeding tube.

Two days after she was born, Adalida underwent a nearly three-hour surgery to successfully remove the tumor.

It was only on May 29, eight days after she was born, that the Tylers were allowed to hold Adalida for the first time.

"It was a relief," Kristin Tyler said. "Before then, just seeing her in the NICU and seeing her laying on the bed and not being able to pick her up, I wasn't used to that ... so when I got to hold her for the first time, it was like that bond was there. I got to connect with her."

Adalida would spend another four weeks in the NICU before being released to go home on June 29, her original due date.

The trip home marked the first time the Tylers had been home in Louisiana together in over three months, and the first time William was able to meet his sister, a milestone that Kristin Tyler said allowed her family to finally "bond."

Once home, Adalida continued her recovery, which included limitations of only laying on her stomach in order to allow her incision from the tumor removal to heal.

Now 5 months old, the infant is hitting all her milestones, including rolling and scooting as she prepares to crawl, according to the Tylers.

Adalida may face another cosmetic surgery in two to three years but is expected to live a normal, healthy life, according to both Nassr and the Tylers.

The couple said they want to share their story to raise awareness of sacrococcygeal teratoma and help other families who may face a similar diagnosis in pregnancy.

"The biggest challenge I faced while I was pregnant was the unknown. It was me going through Facebook, Instagram, any social media platform, trying to find mom groups, somebody that I could relate to that has gone through this similar situation, and I couldn't find anything," said Kristin Tyler. "So if there is any other families or parents out there that do feel like they're alone in this ... they're not."