3 baby girls born in 3 days with 3 heart surgeries celebrate birthday milestone

— -- Three baby girls with Down syndrome and heart conditions born in three consecutive days celebrated their first birthdays together in a joyful photo shoot.

After all three underwent surgeries to repair their congenital heart defects at Boston Children’s Hospital. Now happy and healthy, their mothers decided to celebrate the milestone together in a cake smash photo session dubbed "Three of Hearts."

"When we realized the connection between these three heart warriors, we knew that we had to celebrate in a big way," photographer Nicole Starr told ABC News. "We let them be the stars of the show with just a simple backdrop and classically simple cakes, and their unique personalities definitely stole the show."

The three girls -- Mae, Catherine, and Harper -- first met at a photo shoot celebrating breastfeeding for children with Down syndrome. That shoot was organized by Ella Gray Cullen, the founder of Julia's Way, a non-profit dedicated to helping families re-imagine life with Down syndrome. It was there that the girls' moms discovered their close connection.

"I couldn't believe it at the first photo shoot that our babies were born so close together," Aimee Kadehjian, Catherine's mother, told ABC News. "I thought the cake smash photo shoot would be a perfect opportunity to spread awareness that kids born with Down syndrome are just like all other kids and for the Julia's Way foundation."

Despite the girls' similarities, they all have their own little personalities.

Kadehjian called her daughter Catherine the "serious one."

Cristina Colanti, Mae's mom, said she's always "smiling and babbling."

Harper's mom, Michele Fox, said her daughter has brought "unconditional love, empathy, and compassion to all of us."

Given all the girls have been through in their first year, the mothers were eager to showcase how they are doing now.

Fox said Harper's surgery was difficult not only for the little girl but for her entire family.

"Her surgery was hard on us," Fox told ABC News. "She won't remember anything but I had a really hard time bonding with her until after the surgery."

For the babies and their mothers, the photo shoot was a way to celebrate an important milestone.

"What a journey they have been through in their first year of life," Colanti said. "It was truly worth celebrating."