The National Hospital of Pediatrics created an anus for four-day-old conjoined twins on Thursday, Nguoi Lao Dong newspaper reported.
The two baby girls share a liver, a duodenum (top section of the intestines) and a large intestine. They were born without anuses, and their vaginas are incomplete.
The hospital said it was the most complicated case of conjoined twins in 10 years.
The twins are the first children of Hoang Thi Thach, a 21-year-old woman from the northern province of Ha Giang.
They weighed a combined 4.7 kilograms when they were born. Four days after birth, they suffered respiratory failure and were put on breathing machine.
Dr. Nguyen Thanh Liem, director of the National Hospital of Pediatrics, said the hospital will perform a surgery to separate the twins when they are 5-6 months old at an estimated weight of 12 kilograms.