Susie Kozisek just became a proud grandmother to twins, and she has herself to thank.

The 53-year-old Ventura, Iowa woman gave birth to her newborn granddaughters, Hailee and Hadlee, three weeks ago since their mother was unable to conceive, Globe Gazette reports.

“It means the world to me,” Kozisek said. “I just wanted them to have the chance to be parents. They’re very good at it.”

This isn’t Kozisek’s first time being the gestational carrier for her daughter. Two years ago she gave birth to her granddaughter, Harper on June 24, 2011.

Her daughter, Ashley Larkin, has pulmonary hypertension, high blood pressure in the lungs and heart, which can cause heart failure if left untreated. When a woman becomes pregnant, the condition endangers the life of the mother and unborn child, Medical Daily reports.

A gestational carrier, much like a surrogate, carries another woman’s pregnancy in her womb. An egg and sperm are fertilized using in vitro fertilization. The embryo is then implanted on the carrier’s uterus.

"I heard about the procedure on a talk show and decided to check out the possibility of me doing this for them so they could have kids of their own if they wanted," Kozisek told ABC News. For newborns Hailee and Hadlee, the embryos were kept in storage since October 2010 at the Mayo Clinic.

Despite her age, Kozisek said both pregnancies she carried for her daughter were uneventful. She stayed healthy, and continued to work as a legal secretary. “Everything they tell you can happen because you’re older — diabetes, high blood pressure — didn’t happen,” she said. “I was never under restrictions, never on bed rest.”

Larkin was in the delivery room for both births. “They are miracles,” she said. “They’re good babies, too. They’re content to sleep a lot.”

Dr. Jani Jensen, the Mayo Clinic fertility doctor who performed the in vitro fertilizations for the family, commended Kozisek for her selfless actions.

"They are a testament to the profound love a mother can have for her child," she said. "It is an incredible thing this mother did so her daughter could have children."