After pregnancy, pain in the bone above the hip groove is a common clinical symptom, especially when the pregnant woman is lying on her side or sitting, the pain will be more obvious. What causes this symptom?1. Prolonged sedentary is one of the main reasons for this symptom to appear. As a result of being in the same position for a long time, the body’s blood circulation is affected, and symptoms such as physical fatigue and pain can easily occur. The main cause of this symptom is the pressure on the buttock sulcus and the poor blood circulation. 2. The pain in the buttock sulcus is caused by the enlarged uterus pressing on the adjacent tissues or nerves. 3. Pregnant women secrete a special substance, relaxin, which relaxes the ligaments of the pelvis and causes pain in the bone joints of the pelvis.