Police said they are looking for a man who stabbed a pregnant teenager after trying to rob her early Saturday morning in Dorchester. The 17-year-old female, who is six months pregnant, told police she was going to her boyfriend’s house about 2:15 a.m. when she noticed a man following her from Dorchester Avenue down Dracut Street, Boston police said in a statement. The suspect threatened her with a knife and told her to empty her pockets, the report said, and when she did not comply, the suspect stabbed her upper left arm at least twice. She was taken to Boston Medical Center with non-life-threatening injuries. The teen described the suspect as a black male in a green hoodie, about 5 feet, 2 inches tall, and has a “young face,” according to police. Anyone with information about the suspect can call Boston Police at 617-343-4335.