Cleveland ? Doctors began the first in a series of high-risk surgeries Wednesday to separate 3-year-old twin girls joined at the head.

Doctors hope to separate Tatiana and Anastasia Dogaru, who were born in Italy but are of Romanian descent, through several surgeries in about six months. Without separation, the twins risk dying in early childhood.

The initial surgery lasted all day and didn’t end until early evening. The girls were under close observation in a pediatric intensive care unit. An update on their condition was not expected until today, said Janice Guhl, spokeswoman for University Hospitals’ Rainbow Babies & Children’s Hospital.