Pregnant women’s left chest under the rib pain, may be caused by extrusion of the ribs, but does not exclude pathological factors, such as pregnant women with costochondritis, angina pectoris, myocardial infarction, gastric ulcers, etc., may cause this part of the pain. 1. Physiological factors: pregnant women left rib pain may be due to the gradual increase of the uterus on the surrounding tissues resulting in compression; and if the pregnant woman to maintain a long time the left side of the lying position, the baby’s head or limbs oppression of the corresponding local muscles, resulting in the pregnant woman’s left rib localized pain. There is also the possibility that pregnant women wear too tight clothes, such as wearing a bra with a steel ring fixed compression to the left ribcage caused. 2. Pathological factors: In addition, if the pregnant woman has costochondritis, angina pectoris, myocardial infarction, gastric ulcer, etc., may cause pain in this area. Therefore, if a pregnant woman has persistent pain or severe pain, it is necessary to consult a doctor in time to clarify the cause and give targeted treatment.