A report from the South China Morning News said staff offered the pair compensation.
The local market supervision authority has launched an investigation into the incident and the outlet where the rat was discovered has been shut down.
After video footage of the dead rat in the woman's soup circulated on social media, the chain's shares dropped by 12%, losing £145m in value to reach its lowest level since October previous year, before regaining value.
"If you are anxious about the baby, then we'll give you 20,000 yuan ($3,000) to abort it", Mr Ma says the staff told him.
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. This revelation caused the offer to be upped to 20,000 yuan so that the woman could get an abortion.
Xiabu Xiabu has 759 restaurants in China.
A video of the boiled, gelatinous rodent being pulled out of the pot with its arms stretched out, circulated on Chinese social media site Weibo - and users were angry and disgusted. Some users said that they would never eat there ever again. "I feel like vomiting". On 5 September, the day before the incident, share prices closed at HK$12.16. "I can't believe this", another commented.
"If something happens to her baby how are they going to compensate her? Is a life worth only 20,000 yuan?"
Xiabu Xiabu specializes in hot pot, traditionally a large family meal where various meats, vegetables and other ingredients are cooked at the table by diners in a giant pot of bubbling soup and consumed immediately. Xiabu Xiabu had released a statement which declared that it was "impossible" that a lack of hygiene at the restaurant was to blame for the rat's appearance, but that statement was deleted a short time later.