They’re small but mighty. Born at just 22 weeks, Keeley and Kambry Ewoldt are among the most premature surviving twins to be born in the country. Doctors believe that kids born after 24 weeks of pregnancy have the best chance of survival.

Keeley weighed 1 pound at birth while Kambry weighed just 13.4 ounces.

While pregnant, Jade Ewoldt, the girls’ mother, was diagnosed with twin-twin transfusion syndrome, an abnormal formation of blood vessel connections between identical twins. The condition usually causes premature birth.

Although she had surgery in utero try to correct the problem, she ended up giving birth four weeks later on Nov. 24.

“We know that the national survival is about 10 percent for babies born at 22 weeks,” Dr. Jonathan Klein, a neonatologist at the hospital, told Inside Edition.

“However, we’ve been working very hard with this population for the past over 10 years. We currently have a 65 percent survival rate of kids born at 22 weeks who are admitted to the NICU, which is nearly 150 percent higher than the national norm, thanks to a dedicated NICU, committed nurses, respiratory therapists, and nurse practitioners.”

It’s been a roller-coaster ride for the twins’ parents, Jade and Wesley, who have been with the girls every day since they were born in late November.