If you are not yet clean from your period, of course you will not get pregnant if you have intercourse. Because ovulation does not occur during menstruation, or to put it another way, even if ovulation occurs during menstruation, after sexual ejaculation, sperm and egg combine to form a fertilized egg. Because the lining of the uterus at this time does not have the conditions for implantation, the fertilized egg will be discharged from the body with the menstrual blood. This assumption does not exist, sex during menstruation has no possibility of pregnancy, but it is easy to lead to gynecological inflammation, should pay special attention. This is because when menstruation occurs, the uterine lining is shed and the blood sinuses under the lining are exposed, and bacterial microorganisms invade, easily leading to endometrial inflammation. If the vaginal ejaculation, it is easy to cause the woman to produce anti-sperm antibodies, resulting in infertility.