JIANGSU (BLOOMBERG) - Chinese officials are investigating the husband of a mother of eight after footage of her chained by the neck sparked fears on social media that she'd been trafficked to bear children.

Details relating to the man surnamed Dong would be released "in due course", officials in the eastern city of Xuzhou said in a Tuesday (Feb 8) statement, while guardianship of the children would be determined "according to the law".

Officials had visited local police stations and villages, reviewed archives and consulted legal experts as part of the investigation.

The video of the woman surnamed Yang locked in a village hut in Jiangsu province was widely shared on social media over the Lunar New Year holiday, as users demanded that the authorities investigate.

Many posted past cases of women being trafficked across the world's second largest economy, including footage of a man confining his wife to a potato shed, and discussed the limited rights of rural women.

A preference for baby boys has created a gender imbalance in China, where there are nearly 35 million more men than women.

That combined with traditional demands for a male to continue his family line, in rural areas in particular, has created demand for trafficked brides.

In the Tuesday statement, officials said Ms Yang came from the south-western province of Yunnan, and suffered from speech abnormalities and schizophrenia.

A "family friend" brought her to Jiangsu years ago for medical treatment and to find a "good family to marry", the authorities said.

After getting separated from the friend on that trip, she married Mr Dong in 1998 and later had eight children by him, officials said.

Social media users asked why Ms Yang had been taken so far for treatment and asked if her disappearance had been reported. On Jan 28, lower-level county officials ruled out trafficking in a preliminary investigation.

The city and county authorities will "learn from this incident", the Xuzhou city officials said, adding that Ms Yang had received medical treatment.

"This case is egregious and especially bad," said Ms Wang Yaqiu, a senior researcher on China at Human Rights Watch. "Over the years we have heard many stories about women being forced into villages due to a gender imbalance. This is a widespread phenomenon."