Doctors at a Kentucky hospital have successfully separated conjoined twin girls. Kosair Children's Hospital in Louisville said in a statement that the eight-hour surgery was performed on the 7-week-old girls on Nov. 11. While both remain on ventilators, the statement said they are getting stronger each day. The girls were joined at the chest and abdominal cavity. They shared some heart structures and their livers were connected, according to the statement.
Doctors waited as long as they could to perform the risky procedure, making the decision to move forward because both girls needed increased breathing support. Although their long-term prognosis is unknown, chief cardiovascular surgeon Erle Austin III says doctors are "cautiously optimistic" about their future. Experts say conjoined twins occur once in about every 200,000 pregnancies. (Read more conjoined twins stories.)