A pair of identical twin baby girls born at an Iowa hospital are already making history.

Sisters Keeley James and Kambry Lee Ewoldt were born 18 weeks early, at just 22 weeks and one day gestation on Nov. 24, placing them among the youngest surviving premature babies born at the University of Iowa Hospitals and Clinics, according to the Associated Press.

Their original due date was March 29, a hospital spokeswoman tells PEOPLE.

“I’d never heard of babies being born this early,” the girls’ father Wesley Ewoldt said, according to the AP. “We didn’t have a lot of positive thoughts. They told us from the get-go this is going to be a roller-coaster ride.”

Both babies were about the length of a dollar bill at birth, with Keeley weighing 1 pound and Kambry born at just 13.4 ounces, the AP reported. Dr. Jonathan Klein, medical director of the NICU at University of Iowa Stead Family Children’s Hospital, told the Waterloo-Cedar Falls Courier that Keeley and Kambry are “clearly” among the top four or five youngest babies ever delivered at the hospital.

In previous years, Klein continued,” one child was born at 22 weeks and another at 22 weeks and one day, but neither were twins. Micro-preemies are the smallest of all premature babies.

Mom Jade Ewoldt was 16 weeks pregnant when the girls were diagnosed with twin-twin transfusion syndrome, a rare condition in which identical twins share a placenta, according to the Courier.

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A lot of babies die from the condition, Klein said, and , at 17 weeks, the twins underwent surgery in utero at Cincinnati Children’s Hospital.

Jade’s water broke in the family’s home four weeks after the surgery and she was rushed to the hospital in an ambulance.

“I was so mad and upset and scared,” she told the Courier said. “I was just praying the girls wouldn’t be born at home. It’s overwhelming when you think about these things. So much goes into making sure these two little girls stay alive.”

Babies delivered so early are often born with skin fragile to the touch, trouble breathing, and underdeveloped eyelids. Klein told the publication that he is cautiously optimistic, taking it one day at a time until the twins are doing well one month after their due date.

The babies remain in the hospital and are no longer intubated, the spokeswoman tells PEOPLE. Keeley is now just over four pounds and Kambry weighs nearly four pounds.

Jackson is now a healthy high school senior preparing to graduate in May.