Leg cramps are common, and usually occur during the latter half of pregnancy. The cramps are due to painful muscle contractions and are generally experienced in the calves at night. They are thought to be secondary to a buildup of lactic and pyruvic acids leading to involuntary contraction of the affected muscles, but the exact etiology is unknown.
A Cochrane review found that the only placebo-controlled trial of calcium treatment showed no evidence of benefit in the treatment of leg cramps, but placebo controlled trials of magnesium supplementation suggested a possible benefit (odds ratio 0.18, 95 percent CI 0.05 to 0.60). This was a small trial of 69 pregnant women with persistent leg cramps. The preparation used was magnesium lactate or citrate 5 mmol in the morning and 10 mmol in the evening.
Stretching exercises may be an effective preventive measure. These can be performed in the weight-bearing position; they are held for 20 seconds and repeated three times in succession, four times daily for one week, then twice daily thereafter.
If a cramp occurs, calf stretches (toe raises), walking or leg jiggling followed by leg elevation may be helpful. Other nonpharmacologic remedies include:
- A hot shower or warm tub bath
- Ice massage
- Regular exercise for conditioning, calf strengthening and stretching
- Increased hydration
- Use of long-countered shoes and other proper foot gear
- Stand facing the wall, feet together, about 24 inches from the wall. With the heels firmly on the floor and the body aligned straight at the hips and knees, lean forward to the wall, stretching the posterior leg tissues. Hold this position for 10 to 30 seconds. Repeat five times per session, at least two sessions daily.
Reproduced with permission from Sheon, RP, Moskowitz, RW, Goldberg, VM. Soft Tissue Rheumatic Pain: Recognition, Management, Prevention, 3rd ed, Williams & Wilkins, Baltimore 1996