Contraception rings, although not necessarily harmful, should not be an excuse for family planning, said Rong Qi, a Beijing-based doctor who specializes in gynecology and obstetrics.
"The device is actually the safest and most effective measure to prevent pregnancy for married women with children," said Rong.
The device, usually made from copper or plastic, can stay in the womb for one or two decades without hurting women, she said. However, there are occasionally some side effects, such as bleeding, she added.
An NPFPC officer told the Beijing Times there were no national regulations requiring women to take contraception rings before registering for their children's hukou.
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