Sore legs and lack of energy when walking in late pregnancy is considered a sign of calcium deficiency. This is because in the middle and late pregnancy, the fetus grows faster and requires higher levels of calcium. If the pregnant woman is deficient in calcium, it will easily lead to sore legs and also accompanied by leg cramps. You should take calcium supplements in time, you can take calcium tablets for pregnant women. In addition, you should pay attention to eating products with high calcium content. You can eat more seafood or get more sunlight, which will help promote the absorption of calcium. In the middle and later stages of pregnancy, due to the increase of the uterus is more obvious, compression to the inferior vena cava reflux, resulting in poor blood circulation, will also be prone to leg pain, weakness. In this case, care should be taken not to stand or sit for a long time, and bed rest should be taken to improve this phenomenon. If the symptoms persist and get worse over time, it is recommended to seek medical attention.