Hello, and I hope I can help you today. First of all, I want to reassure you that if you and your girlfriend have not had unprotected vaginal sex since her last period, there is no way she could be pregnant. There are many reasons why women may have irregular periods, meaning menstrual cycle that is not typical. Some women can have spotting when are not supposed to have their period, or have it skip once in a while. This can because by many factors, including stress, weight gain or loss, travel, or even worrying about getting pregnant. So there is a possibility that your girlfriend is just sick and because of the stress of her body, she is having irregular bleeding. What I would suggest in the meantime is telling your girlfriend not to worry too much, to concentrate on getting better, and if she continues to bleed from more than a week she should be evaluated by a women s health provider. But again, pregnancy is not something you need to be concerned about if you ve not had sex since her last menstrual cycle. I hope that I was able to adequately answer your question at this time, and that my advice was helpful. Best wishes, Dr. Brown