One of the conjoined sisters separated early today has been returned to surgery. The one-year-old girls were separated at the head in a risky procedure that took 22 hours at UCLA. One of the girls, named Maria Teresa, developed a hematoma related to surgery and was brought back into the operating room. The lead neurosurgeon says the outlook for both twins remains positive, however. Doctor Jorge Lazareff says the hematoma is a collection of blood on the surface of the girl´s brain that increases pressure on the organ. Doctors are removing the buildup to speed recovery.

A UCLA Medical Center spokeswoman reports the additional surgery is taking longer than expected. A news conference is now being pushed back to 4:30 this afternoon. The girls were separated at the head in overnight surgery.