Breast tenderness 1 week after intercourse may be pregnancy or premenstrual syndrome, whether it is pregnancy needs to be based on urine pregnancy test or blood HCG test. 1. pregnancy: early pregnancy due to changes in hormone levels in the body, women can gradually increase the size of the breasts, nipple enlargement, self-consciousness of breast swelling and pain. 2. Premenstrual syndrome: women of childbearing age, 1 to 2 weeks before menstruation can be preceded by headache, lumbar sleepiness, breast distension, abdominal distension, constipation and other physical discomforts as well as irritability, anxiety, memory loss and other mental behavioral changes, i.e., premenstrual syndrome. For the diagnosis of early pregnancy, nausea, vomiting, frequent urination, breast swelling and pain and other symptoms are only suggestive of the significance of the need for a definitive diagnosis of the blood HCG test or urine pregnancy test to determine, if you are not sure whether the pregnancy, you can go to the Obstetrics and Gynecology clinic for consultation.