Yan Ruizhi, 29, a nurse at a branch office of the Xishan district center for women and children's health in Kunming, had a premarital checkup with her husband in 2009 as part of a promotion on the first day the center offered free premarital physical examinations.

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Yan's office is located on the first floor of the district government office building. The marriage registration desk is at the far end of a long corridor with several medical checkup rooms, "The setup encourages more people to get the checkups," said Yan.

The health check requires personal information, including a family history of disease and the patient's previous treatment records. A blood test covers contagious diseases, including HIV/AIDS, hepatitis and syphilis.

In the decades after the establishment of the People's Republic of China, a bride's virginity was of paramount importance. At the time, the premarital checkup included an examination to ensure that the hymen was intact.

A retired nurse from the center told Yan that the forms were stamped to indicate an intact hymen and sometimes the information was leaked, deliberately or accidentally.

"Nowadays, young men care less about virginity, and we also have better regulations to protect the privacy of the person being tested," said Yan.

China's marriage registration rules mean that premarital checkups are no longer compulsory. As a result those who undergo the procedure are no longer required to present the results to the marriage registrar.

Yang Wanli