The 29-year-old woman was arrested after an ambulance was called to an address on Aldwick Road, Bognor Regis, at 8.37am on Wednesday where a baby girl was confirmed dead at the scene, Sussex Police said.
The mother, Ginaite Suminaite, was taken to St Richard's Hospital, Chichester, for urgent medical treatment. After being released by the hospital, she was arrested on Friday and charged with murder on Saturday, The Press Association reported.
She will appear at Crawley Magistrates' Court on Monday.
Sussex Police confirmed they are not looking for anyone else in connection with the murder.