Leg pain in the second and third trimester of pregnancy is mostly caused by rapid fetal pain, which gradually enlarges the uterus and moves the abdomen forward. In order to maintain the balance of the body, the upper body leans back compensatory, resulting in excessive lordosis of the spine and continuous tension of the extensor dorsi, which leads to excessive fatigue of the back and is easy to cause backache. Generally speaking, symptoms can be alleviated after rest.
In addition, if the pregnant mother lacks calcium during pregnancy, it will also cause leg pain.