A 53-year-old woman has given birth to her own twin grandchildren, Medical Daily reported.

Susie Kozisek successfully delivered twin girls after acting as a gestational carrier for her daughter, Ashley Larkin. Larkin had been diagnosed with pulmonary hypertension, a condition caused by high blood pressure, which prevented her from safely becoming pregnant.

Gestational carriers are typically used when a woman is unable to carry a pregnancy but wants to have her own biological children. The biological mother and father undergo in vitro fertilization and their fertilized embryos are then implanted in the carrier’s uterus.

Dr. Jani Jensen, who performed the in vitro process for Kozisek and Larkin, told ABC News that while this situation is unusual, it is fairly common for a family member to act as a carrier.

"It's unusual for a mother to act as a gestational carrier for her own child, and she was at the older end of the spectrum for pregnancy," Jensen said. "But she was a good candidate, because she'd carried previous pregnancies successfully and was in excellent health."

This is the second time that Kozisek has acted as a gestational carrier for her daughter. Kozisek also carried and gave birth to Larkin’s 2-year-old daughter. Both pregnancies did not have any complications.

"I've always been close with my mom even before this, so that hasn't changed, and I'm grateful she will have such a special bond with her grandkids," Larkin told ABC News.

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