Leg pain during pregnancy is mainly caused by the uterus and hormonal changes, in addition, calcium loss may also lead to sore thighs. 1, the uterus increases: after pregnancy, the size of the uterus and fetus gradually increases, which will compress the back of the spine and nerves, and at the same time, the weight of the legs and feet increases, so it is easy to have sore legs; 2, calcium deficiency: due to the needs of the growth and development of the baby during pregnancy, a larger amount of calcium is needed, if the pregnant mother If the pregnant mother did not supplement in time, will also cause soreness in the thighs; 3, hormonal changes: after pregnancy, changes in the body hormone levels of pregnant women, sitting and standing or after exertion can cause soreness in the thighs. It is recommended that pregnant women can use hot water to soak their feet during pregnancy, avoid standing for a long time, pay attention to rest, elevate the lower limbs as much as possible, which is conducive to venous return; usually consume more nutrients and trace elements, a balanced diet, and also consume more fresh vegetables and fruits; take calcium supplements in time, get more sunlight, and take calcium supplements and vitamins under the guidance of a doctor if necessary. Pregnant women should pay close attention to the observation of fetal movement, if there are abnormalities in time to the hospital, to do a good pregnancy checkup.