15 weeks pregnant breast swelling and pain may be early pregnancy reaction to reduce performance, but may also be the manifestation of fetal arrest. 1. Early pregnancy reaction to reduce: women’s early pregnancy due to increased levels of estrogen and progesterone in the body, stimulating the breast ducts hyperplasia development, congestion and edema, there will be breast swelling discomfort, generally after ten weeks of pregnancy with the increase in hormone levels no longer continue to increase or tend to stabilize, the symptoms of breast swelling will be reduced or disappeared, belong to the normal physiological phenomenon. 2. Fetal termination: 15 weeks pregnant breasts do not swell and pain may also be the manifestation of fetal termination, the embryo stops developing during pregnancy after the hormone level drops, there will be breast swelling and pain symptoms will be reduced or disappeared, nausea, vomiting, and other phenomena disappeared and so on, you can do ultrasound in time to check the development of the embryo, if it is the result of fetal termination need to be terminated in a timely manner and check the cause of fetal termination after treatment.