Pregnancy cramps are sudden, involuntary contractions of one or more muscle groups that cause severe pain in the thighs, calves, and legs, often occurring at night during the middle and late months of pregnancy. There are many causes of pregnancy cramps. Although generally harmless, cramps can temporarily immobilize the pregnant woman, causing pain and affecting her sleep and movement.

Pregnant women in the 21st week of pregnancy are prone to varicose veins due to the growing fetus and increased levels of the hormone progesterone, which puts pressure on the veins in the mother's legs. In addition, pregnant women in the 21st week may experience other symptoms such as bloating, abdominal distension, back pain, and bleeding gums.