The young woman, already a widow and a mother of a young child, was planning to tie the knot with another man. The couple, however, separated in April when the woman found out that she was pregnant.
She returned to her parents' house and earlier this month, in her eighth month of pregnancy, deliberately caused a miscarriage in the toilet. She had not told anyone she was pregnant, including hospital doctors.
"She gave birth to a child in a public lavatory and then, investigators believe, threw her newborn baby into the toilet, where the child, who was born healthy, drowned," a spokesman said.
Shortly afterwards, the woman was taken to a hospital with serious bleeding.
A criminal case has been opened. If convicted of killing her child, the woman could face up to five years in prison.