Having breast tenderness when you are about to have your period is not necessarily a sign of pregnancy. Although breast tenderness can occur when you are pregnant. However, if a woman has breast enlargement or some other pathology of the breast, it can also easily lead to breast swelling and pain. Therefore, if you want to know if you are pregnant, the first thing to do is to see if your period is delayed. If your period is delayed and accompanied by swollen breasts, nausea and poor appetite, the probability of pregnancy is relatively high. Usually a urine test or a blood test for HCG will clarify whether you are pregnant or not. Also, if you are pregnant, your uterus will change. If you have stopped menstruating for more than 40 days, you can usually see the pregnancy sac with an ultrasound.