Doctors in Houston have successfully separated twin toddlers who were born in 2016 conjoined at the chest and abdomen.
A spokeswoman at Texas Children's Hospital says 13-month-old Anna and Hope Richards were in good condition after the procedure yesterday.
Lindsey Fox says separation surgery was done on January 13 and announced on Tuesday.
Fox says the twin sisters join two brothers and their parents, Jill and Michael Richards of North Texas.
Fox declined to provide more specifics about the family as the parents focus on their daughters' recovery.
Officials say a routine ultrasound revealed the girls were conjoined.
The twins were born premature, at just over 35 weeks, on December 29, 2016, at Texas Children's Pavilion for Women. Their combined weight was nine pounds, 12 ounces (4.4kg).
"These are the kind of procedures you plan for the worst and hope for the best and we're blessed that this is the best case scenario," said Dr Oluyinka Olutoye of Texas Children's Hospital in an interview.
"These Conjoined twins are what are called thoraco-omphalopagus twins which is just really a fancy way of saying that they were joined in the thorax and the chest and in the upper abdominal region," he explained.
"Well my hope is that this girls will grow up to have healthy lives and live nice productive lives and that they would grow up to be twin sisters, like nobody would ever be able to tell what the initial part of their life was unless they decide to tell others what it is."
Another doctor from the surgery team spoke to emotional family members of the twins after their operation.
"The hearts are separate and there they were doing fine. They're like their blood pressure didn't change. They handled it just fine," the doctor said.