Thirty-three-year-old Sarah Lane Toney of Myrtle Beach, is already in custody from an arrest on unrelated charges.
WPDE-TV reports the new charge against Toney is a result of her actions that led her baby to become lost in a creek near Socastee, west of Myrtle Beach.
Officials say Toney will be served with an arrest warrant by the end of the day.
Meanwhile, emergency workers on the South Carolina coast have resumed their search for the 5-month-old baby Grace a day after her mother told police she threw her in a creek. Officials were going to resume their search at 8 a.m. this morning but bad weather delayed them for several hours.
Lt. Denis says they have a woman in custody who told them she threw the baby in the water. Crews are still searching pic.twitter.com/fGA24y6TTQ— Erin MacPherson (@ErinWPDE) November 3, 2015
Police say they were called to the scene on Tuesday by a resident who found the mother on her back porch and was told by her that she went in to the river with the baby but no longer had her.
The Associated Press contributed to this report.