A suspected baby trafficking case in Fuping county, Shaanxi province, continues to develop as more couples claim they were duped into giving up their newborn babies.

The county police confirmed on Wednesday that the parents of 10 children delivered at Fuping Maternal and Child Health Care Hospital have reported their babies were also taken away by Zhang Suxia, deputy director of the hospital's maternity department.

Wang Yanyan, a farmer in Fuping, said she gave birth twins on May 31 and was told by the doctor the babies suffered from "congenital diseases" and would not live past three years.

Wang Yanyan (center) says she was tricked into giving up her twin babies by Zhang Suxia, an obstetrician at the Fuping Maternal and Child Health Care Hospital in Shaanxi province, who later sold them. Wu Jiang / for China Daily

"She told us to give up the babies and never let us look at them," Wang said.

However, Wang said she had several prenatal checkups during her pregnancy and the results showed she and her fetuses were normal.

Dong Pengfei, a local farmer in the county's Xuezhen township, reported to police that his wife gave birth to a baby boy in the hospital in 2006 and the doctor said the newborn had congenital defects and persuaded the parents to give him up.

The doctor took the baby away without allowing the couple to see him.

Yang Jianlong, chief officer of the county criminal case department, said, "Because the cases reported to police mostly happened some time ago, the investigation will take some time."

Zhang, the 56-year-old doctor, is suspected of having persuaded couples to give up their babies over the past eight years.

She was exposed only recently when a couple became suspicious and reported her to the police.

On Monday, police located the couple's baby boy and returned him to his parents.

Lai Guofeng, the baby's father, said he is now concerned about his son's health and he has yet to decide whether to sue the hospital.

On the night of July 16, Lai's wife, Dong Shanshan, gave birth to a baby boy at the hospital. Zhang told them the child suffered from syphilis and hepatitis B transmitted from the mother and would not survive.

Zhang did not let the couple see their baby but said he had already been taken away.

Lai questioned the doctor's diagnosis and took his wife to another county hospital for syphilis and hepatitis B tests the following day. Two days later, the test results showed his wife was free of both diseases.

On July 20, Lai contacted police who investigated and found the baby in Henan province 20 days after he was born.

Zhang was detained by police and confessed she had sold the baby for 21,600 yuan ($3,500) to two people from Shanxi province in the early morning of July 17.