The 38-year-old Periyasami, with wife and three children, had called the woman to help him in household works and allegedly sexually assaulted her in the absence of members of his family a few months ago, police said.
This continued for some more days, resulting in the 30-year-old woman becoming pregnant, police said.
The woman's mother lodged a complaint with the All Mahila Police Station at Pollachi, based on which Periyasami was arrested, they said.
