The mother of the child, Rikta, tried to flee after throwing her son in a pond next to their house in Narail district early in the morning but local people stopped her, police was quoted as saying by bdnews24.Com.
"The body of the child was recovered from the pond," said police. "The mother has been taken into custody."
The couple were going through a rough patch for the past several days, sub-inspector Manik Chandra Saha said.