As of 11 a.m., Friday, Aug. 23, both Maria Teresa and Maria de Jesus Quiej Alvarez remain in serious condition with stable vital signs in the Pediatric Intensive Care Unit at UCLA’s Mattel Children’s Hospital.

Maria Teresa remains on a ventilator but is being eased off of sedation. She underwent a 90-minute procedure on Thursday, Aug. 22, which allowed doctors to remove blood from an area in the back of the brain that was too sensitive to address in earlier surgeries. Maria Teresa underwent similar procedures on Friday, Aug. 16, and on Tuesday, Aug. 6, the afternoon of the initial separation surgery.

Her sister, Maria de Jesus, continues to be alert and active. Doctors remain cautiously optimistic about the long-term prospects for the recovery of both girls.

The one-year-old Guatemalan twins, who were born conjoined at the head, were separated at UCLA on Aug. 6 in a nearly 23-hour surgery.