Ovulatory bleeding has little chance of pregnancy if you have sex during this period, mainly because of the following points: a. Ovulatory bleeding is alkaline, and the activity rate of sperm in the alkaline solution will be affected accordingly, so there are not many sperm that can move quickly, and the chance of reaching the abdomen of the fallopian tube and combining with the egg will drop significantly, so the chance of pregnancy will also drop significantly. Secondly, during ovulation, the endometrium in the uterine cavity sheds and causes bleeding, and the sperm enter the uterine cavity and are expelled with the bleeding, so clinically the chance of pregnancy is relatively small. In addition, it is best not to have intercourse during ovulation because it may lead to inflammatory reactions in the reproductive tract and pain in the lower abdomen or increased vaginal discharge.