ENGLEWOOD, Colo. -- Their parents call them "miracle babies," but their lives have been hard.

About 13 percent of American babies are born premature, and inside Swedish Medical Center's Neonatal Intensive Care Unit, there's a daily life or death battle for Colorado's tiniest survivors.

To a couple who desperately wanted children, the news of twins came as a welcome surprise.

"It took us about a year to get pregnant," said Ryan Hoytink.

But the surprises were just beginning for Heather and Ryan Hoytink.

"I had a normal pregnancy. I didn't have any complications," said Heather Hoytink.

"Then to have Heather say, 'I think my water broke. It can't break this early there's no way,'" said Ryan with a smile.

Their twins didn't agree. Alexandra and Graham came into this world just 27 weeks two days into the pregnancy, more than three months early.

"She was one pound 13 ounces. He weighed two pounds," said Heather. "Her face was incredibly bruised."

"It's been a really tough journey." - Heather Hoytink

Photographs show their little bodies were the size of a Pepsi can.

"The first two weeks are the ones you'd like to forget," said Heather, eyes filling with tears. "Primarily because you're just so concerned if they'll make it, and you're just so scared."

But more than ever before, there's hope for these babies thanks to major advancements in neonatal technology.

"I think their prognosis is very good," said Dr. Delphine Eichorst, a neonatologist at Swedish Medical Center.

She said medical breakthroughs have dramatically changed neonatology in the last two decades.

"It's the medication and the type of ventilators we have that made a huge difference in babies of their age surviving," she said. "These therapies have not only allowed babies younger to survive, but they have allowed them to survive better."

In addition, new practices such as private rooms help put preemies and parents at ease.

"As babies brains develop they need to have a large control over their environment since they're not inside anymore," said Eichorst.

Alexandra and Graham are now nine weeks old, both weighing in at more than five pounds.

"I think the most exciting part of our night is putting them on the scale. To see how much they've grown -- an ounce -- that's huge," said Ryan. "It's a miracle."

A miracle made possible by technology that allows miracles to happen every day.

And for the Hoytinks, that's once again a welcome surprise.

"It's been a really tough journey," said Heather. "But one that makes you feel really good when you look at them today and they look like healthy, thriving, normal babies."

The Hoytink's will probably be able to take Alexandra home in 30 days and Graham in 45 days.

They said their faith and support groups at Swedish Medical Center helped them get through this.