Thakur, also a key accused in the 2008 Malegaon blasts, was yesterday taken to Jawaharlal Nehru Cancer Hospital, where doctors conducted tests on her, they said.
Heavy police force was deployed from the Central Jail to the cancer hospital.
Once the test reports are out, it will be decided whether she needs to be shifted to the hospital or not, for regular treatment, police said.
Thakur was brought from Mumbai to Bhopal last year for trial in the murder case of former RSS worker Sunil Joshi, who was killed in Dewas on December 29, 2007, following which a case was registered against her and others by the Madhya Pradesh police. The matter was later taken over by the NIA.