The incident took place last night at 11:30 PM when Pooja, mother of the child, flung the baby soon after she delivered him at her home in Ajmal Palace, they said.
The accused was married to a diamond worker Jignesh Shapariya in February this year.
Police Inspector M N Parmar said that probably Pooja threw the baby boy because she didn't want a child within a year of marriage.
Complainant Vasubhai Sabalpara, one of her neighbours, brought the incident to light. However, it is unclear why she threw the child.
According to police, neighbours and eye-witnesses called the ambulance service and admitted the new-born to SMIMER hospital, run by the Surat Municipal Corporation but the child died.
Police have registered a murder case under Sec 302 of the Indian Penal Code and are investigating the exact reason behind the step taken by the mother.
Pooja has been admitted to SMIMER and her condition is being monitored, they said, adding that women police are at the hospital.
Her family members are bein interrogated, police said.