West Yorkshire Police believe Laura Murgatroyd, who is missing from the Calderdale area, is with a tot under the age of one.
They are appealing for information to help trace her.
The 26-year-old was last seen at 2.13pm on Friday, June 22, at Crawford Avenue in Bradford.
She is described as white, 5ft 1in tall, of slim build. She has long red-purple hair, speaks with a Yorkshire accent and is of a light complexion.
Laura, or anyone who sees her, is asked to call Calderdale Police on 101, quoting log 984 of June 22.