However, some new mothers are still posting notices on online parenting forums offering to sell their "excessive milk".

A mother in Shanghai, who gave her surname as Hu, wrote in a notice on ganji.com that her refrigerator was full of her breast milk, and she would sell it for 20 yuan for a 100-milliliter bag.

Each bag was labeled with the date it was expressed, and details about the size and brand of the storage bags were provided in the notice.

But Hu said that she has not sold a single bag since she posted the notice a week ago.

"That's fine," Hu said. "We don't need that money to live on. We just didn't want to see the precious milk going down the drain."

Huo Xiaohua, a Shanghai native who gave birth to a boy a week ago, said she would never feed her baby with anything produced by other people, let along strangers.

"It's creepy," the 27-year-old mother said. "If I didn't produce enough milk, I would prefer imported powdered milk. Who knows what's inside those bags?"

According to a regulation introduced by the Ministry of Health, human breast milk is categorized as a "special food source" that cannot be used as a commodity for sale or manufacturing.

Zhang Junping, a gynecologist at the Obstetrics and Gynecology Hospital affiliated to Fudan University, said he thinks the health of the milk donor and the risk of babies being allergic to the milk are the greatest concerns.