Leg cramps affect almost half of all pregnant women.footnote 1 The cause of leg cramps during pregnancy is not fully known, but they may be caused by reduced levels of calcium or increased levels of phosphorus in the blood. Leg cramps are more common in the second and third trimesters of pregnancy and happen most often at night.
There is no proof that increasing your intake of calcium or potassium will prevent leg cramps.footnote 1
If you get a leg cramp:
Straighten your leg.
Flex your foot so that your ankle and toes point up (toward your head).
Massage your calf.
Walk around to stretch your calf.
Avoid pointing your toes when you stretch your legs.
Although uncommon, a blood clot can form in a deep vein of the leg (deep vein thrombosis, or DVT) during pregnancy. DVT can be life-threatening and requires medical treatment.
Symptoms of DVT include severe leg pain or tenderness (not cramps), swelling of the leg and foot, and fever. The leg may have a bluish (cyanotic) or pale color and may be either hot or cold to the touch. If any leg pain persists (especially with leg swelling), contact your doctor immediately.