NANNING, Jan. 7 -- A pair of Chinese conjoined twin sisters, who shared the same liver, are developing normally according to their first hospital checkup since they were separated in August 2013, a hospital source said Tuesday.

The twin sisters, born on June 14 and separated on August 8, have grown to 8.4 kg and 8.2 kg in weight, and 69.5 cm and 69 cm in height respectively, said Yang Tiquan, a surgeon at the No. 1 Affiliated Hospital of Guangxi Medical University.

Their height and weight are no different from that of their peers, said Yang.

The twins, called "Damao" and "Xiaomao," lost parts of their liver after separation, but have recovered normally, he said.

"Liver has strong regeneration capacity," he said. "Their livers have grown and are normal in shape and size in ultrasound examinations."

They have slight anemia and will improve after better nutrition, Yang said.

The occurrence of conjoined twin sisters is estimated to be 1 in 200,000 births. It's even rarer for them to share the same liver. There have been no more than 10 successful separation operations on conjoined twins in China, he said.

Conjoined twins are identical twins joined in utero. Most conjoined twins are stillborn, and many pairs born alive have seriously debilitating abnormalities.