Leg Cramps
Leg cramps are defined as painful, involuntary contractions of the muscles in the legs or feet and appear to increase during pregnancy.
Although electrolyte imbalance is the likely top causal factor, supplementation of the nutrients involved in muscle contraction has not been shown to effectively manage leg cramps during pregnancy.
Therefore, leg cramps likely have – as of yet unidentified – possible other causes, and nutrient supplementation is not recommended for the prevention of leg cramps during pregnancy (unless a woman has been determined to be deficient).
However, physical exercise can improve circulation which could be a secondary factor in the development of leg cramps. Women also need to make sure they replace any electrolytes lost through sweating so cramps are not made worse.
Women need to call their HCP if they experience painful leg cramps that severely disrupt their sleep and ability to function during the day. HCPs can test for possible nutrient deficiencies and/or offer management suggestions.
Background
Leg cramps is a common, yet underdiagnosed sleep disorder occurring most often in the third trimester of pregnancy. It is characterized as sudden, painful, and involuntary muscle contractions, usually of the calves or feet.
Leg cramps, on average, occur once or twice per week (typically at night) and although they only last seconds to minutes, they can be very painful, disrupt sleep, and lead to a decrease in a woman’s quality of life – depending on severity.
For comparison: Restless Leg Syndrome, more recently renamed Willis-Ekbom disease, is a condition that occurs frequently during pregnancy and causes unpleasant leg sensations accompanied by an irresistible urge to move the legs.
Causes
The exact cause of leg cramps is not known; however, during pregnancy, leg cramps are assessed to be caused by nutritional factors, lack of physical activity, venous insufficiency, or a possible underlying disease.
Electrolytes are necessary for muscle contraction and relaxation by aiding nerve impulse conduction and regulating fluid balance; when there is an imbalance in the ratio of electrolytes to fluid in the body, cramps occur.
Calcium, Potassium, and Sodium: essential for muscle contraction; deficiency causes muscle cramps
Magnesium: essential for the transport of calcium, sodium, and potassium across cell membranes; aides muscle contraction and relaxation
Venous insufficiency is defined as poor venous circulation – usually in the lower part of the body such as the legs and pelvis and has been theorized to be a possible contributor to leg cramps. Venous insufficiency is more common during pregnancy due an increase in blood volume, a decrease in blood pressure, and a higher prevalence of varicose veins.
Leg cramps associated with pregnancy may also occur due to periods of prolonged inactivity, such as sitting for an extended period or lying in bed at night. Physical exercise can help promote blood flow circulation, as well as decrease the symptoms associated with varicose veins.
Management
Currently, there is no standard treatment for pregnancy-induced leg cramps. Various methods have been used to treat them, including medications, electrolytes, and vitamins, as well as lifestyle modifications.
Of these methods, there is no clear benefit to pain relievers, anti-epileptic drugs (based on muscle contraction), stretching, compression, magnesium, or other nutrient supplementation on the prevention and management of leg cramps.
Various electrolyte supplementation has not been shown to be effective, despite what could be a clear cause of leg cramps. However, this conflict may be due to poor study design, lack of consistent methodology, and small study sizes.
Evidence is especially weak and inconsistent regarding supplemental calcium and magnesium; additionally, it can be easy to take too much magnesium which can lead to nausea and diarrhea. However, if a woman is found to be deficient in either nutrient, supplementation may be recommended. Women should not take any supplements without talking to their HCP first.
Physical exercise can help increase blood flow in the lower limbs and is of significant overall benefit during pregnancy. Exercise can also help reduce swelling as well as pain caused by venous insufficiency and varicose veins.
Note: Exercise can also cause muscle cramps, especially intense exercise that can lead to excessive sweating. Women who perform intense exercise, or even moderate exercise in warm conditions, need to replace electrolytes lost with sports drinks.
Action
When a leg cramp occurs, immediate stretching, massaging, or moving the leg/muscle may stop the cramp. Heat/ice compresses may also help, especially if the pain persists after the cramp has resolved. Women can also try calf or quadriceps stretching just prior to going to bed. Trial and error regarding these methods may be necessary due to a lack of evidence regarding most effective techniques.
Women who are experiencing painful leg cramps severely enough to disrupt sleep should call their HCP, who can perform a physical assessment and may order lab work to assess nutrient, thyroid hormone, and glucose levels.
Although there is no known management method that can completely eliminate leg cramps, regular exercise and proper hydration may be of benefit for not only leg cramps, but swelling, varicose veins, cardiovascular health, and weight management as well. Further, regular exercise can help promote better sleep.
Women should also consider sharing and submitting their experience below regarding leg cramps during pregnancy. This can help other women learn additional perspectives regarding this concern and how to potentially manage symptoms.
Resources
Leg Cramps (U.K. National Health Service Inform)
Muscle Cramps (StatPearls/NCBI)