The well-known chain, Xiabu Xiabu, was closed for an investigation by health officials after the incident occurred and stock hit the lowest level in nearly a year after news spread, the BBC reports.
The chain also offered a compensation price of 5,000 yuan.
Weifang.sdnews.com reported that a customer at an Xiabu Xiabu outlet based in Weifang city in the Shandong province found a dead rat in a hotpot meal on 6 September. He alleged that one staff member had offered 20,000 yuan ($2,900) for an abortion if she was concerned about the baby's health.
The woman's husband, named as Mr Ma, said restaurant staff had told him: "If you are anxious about the baby, then we'll give you 20,000 yuan to abort it", according to Shanghai-based Kankan News. "I'm never going to eat hotpot outside again", said a Weibo user. "I feel like vomiting".
On 11 September, the company's share price hit its lowest level since October a year ago. Its discovery received particular attention online because of the way that the restaurant's staff chose to deal with the situation. Xiabu Xiabu and one of its rivals, Haidilao, have reported surging sales and an expanding network of restaurants.
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Another shocked user said: "If something happens to her baby how are they going to compensate her?"
Xiabu Xiabu initially released a statement Saturday night saying that it had "ruled out the possibility that an unhygienic environment has caused the rat to appear", but that statement was later deleted.
Hotpots are prepared with a simmering pot of soup stock at the dining table and contain a variety of east Asian foodstuffs.
Health officials investigated the restaurant and found no traces of rats, but shut down the location for other violations, including pooled water in the food processing areas and using produce suppliers without full qualifications.