A Utah woman is pregnant with two babies, but they're not twins.

Angie Cromar was born with a rare condition called didelphys, which means she has two uteruses. It didn't pose a problem for her previous pregnancies, and the 34-year-old has given birth to two healthy children before.

But this time, she's conceived in both uteruses. During her first ultrasound exam, Cromar and her doctor discovered that she's carrying two fetuses at different stages of development, one slightly older than the other.

"[He said] I'm five weeks and four days in one, and six weeks and one day in the other," Cromar told her local TV station, KTLA.

"Angie and I both had the look of surprise," Dr. Steve Terry, Cromar's OB/GYN told another Utah TV station, KSL.

The chances of this happening are estimated to be one in five million. "Probably less than 100, so far, worldwide, have been reported," Terry said. "So she's a member of a small, elite club."

Cromar herself is a labor and delivery nurse, and knows the complications her condition can bring: chances of pre-term labor and low birth weight.

"Oh, I'm a little nervous, just because I know what can happen, but I'm really excited," she told KSL.