Villagers allege that the woman, Ruchi Rawat, collapsed and died after she was beaten on her stomach with sticks during a police raid for fake liquor. The local police, however, insist that she died of a heart attack.
On Sunday, following a tip-off, four or five policemen went to Ruchi's village. During checks at places suspected to be involved in the spurious liquor sale, Ruchi's family reportedly ran away but she was left behind because of her condition. When she tried to run, policemen allegedly beat her with sticks. A woman claims Ruchi was kicked in the stomach.
When she died a short while later, a mob surrounded the police team, which managed to escape.
A senior district official, Rahul Yadav, said the woman's family may have been involved in the illegal liquor trade.
"Three people were arrested and taken to the police station. Two hours later, it was found that a pregnant woman had died. They could have also been involved in illegal liquor business. They might have tried to escape and in the attempt she died," Mr Yadav said.
The police, he said, believe she tried to run and died in that attempt.
A police officer, Sushil Singh, denied the role of policemen in the death. "The police neither went to her house nor did they have any confrontation with her. All these accusations are completely false," he asserted.
There is anger in villages, with people demanding a murder case against the policemen who raided Ruchi's village.