Final answer:
Leg cramps and numbness during pregnancy are often due to circulatory issues caused by pressure from the growing fetus, and are exacerbated by the normal physical changes during the third trimester.
Step-by-step explanation:
Leg cramps and numbness during pregnancy are common phenomena that can be attributed to several factors. One significant cause is the circulatory problems that develop due to the pressure the growing fetus exerts on blood vessels, particularly in the legs. This pressure can lead to clots and impede blood flow, causing cramping and numbness. Additionally, the uterus's expansion and weight gain during the third trimester put a strain on the body, exacerbating these symptoms. Swelling of the lower extremities, varicose veins, and heartburn are also related issues due to the increasing size of the uterus and hormonal changes affecting the vascular system.