A team of doctors will begin the high-risk surgery of separating 2-year-old conjoined twin girls at Stanford University's Lucile Packard Children's Hospital in California Tuesday.
Angelina and Angelica Sabuco, who together weigh 55 pounds, share a liver, chest and abdomen.
Their mother, Ginady Sabuco, says it's getting more difficult for her daughters to move around, and she is praying her girls will survive the surgery.
"We want them to live normally," she said. "When they argue, they can be alone. When they play, they can play together or apart. When they don't want to see each other, they won't have to."
"I hope and pray that everything will be okay," she added.
The lead surgeon, Dr. Gary Hartman, said keeping the girls conjoined could pose serious risks to their health.
"There are two concerns. One is the unknown: is there something we haven't identified. The other is the separation of the liver," he said.
The surgery is expected to take nine hours.
"Our expectation would be that we will have two healthy girls at the end of the operation," Hartman said.