A 33-year-old Pittsburg woman was pulling out of a parking space in the 2100 block of Loveridge Road and almost hit the other woman with her vehicle, Pittsburg police Lt. Ron Raman said.
The victim got out of her car and the two women got into an argument, Raman said.
The suspect struck the victim several times with a sharp metal weapon, causing superficial injuries to the woman's arms and chest, he said.
The victim, who is in the early stages of pregnancy, was taken to a hospital where she was treated and released, Raman said.
No suspect information was available.
Anyone with information about the suspect is asked to call the police tip line at (925) 427-7369.