Swelling in the feet and lower legs is one of the most common pregnancy-related discomforts. Compression socks are designed to alleviate swelling and help reduce your risk for varicose veins, blood clots, and deep vein thrombosis (DVT.) Wearing compression socks during pregnancy also helps to support the work of your cardiovascular system and promote healthy blood flow. Compression socks can be worn during months 3-9 of pregnancy and as long as swelling continues postpartum.