question: My gf has a regular 30-31 day cycle every month and her LMP was on 31.7.13. We had unprotected sex on 24.8.13. I didnt ejaculate inside bt i cant b sure.. Now she had unwanted-72  within 18 hours.. Bt she is mentally very much stressd ryt now.. I am too worried for her.. Now wat cn i do to confirm and ensure that is not pregnant? Also how much there is too worry?? How much time has to pass before she has withdrawal bleeding?? Wat shud b our next? Please help us out