Hello. I m Dr. Christensen. I can understand your and your girlfriend s concerns about an unwanted pregnancy. However, if three home pregnancy tests have been negative, pregnancy probably isn t the issue here. There are a number of conditions, aside from pregnancy, that can cause a woman to skip one or more periods: thyroid disease, ovarian cysts, severe stress, autoimmune diseases (e.g., lupus), excessive exercise, obesity, extremely low body weight, pituitary dysfunction, certain medications and several recreational drugs can all cause menstrual disruption. Your girlfriend needs to see her physician. In the unlikely event she is pregnant, she can discuss her options for terminating her pregnancy if she so desires. Since she has already missed two periods, she would probably be beyond the point where pills would be effective; medical abortions should be completed within 9 weeks of a woman s last normal period. Again, though, the cause for your girlfriend s interrupted periods must be identified before any attempts to terminate a non-existent pregnancy are attempted. I hope that answers your question, and I hope things turn out well!