Oral magnesium for relief in pregnancy-induced leg cramps: a randomised controlled trial

Leg cramps are common in pregnant women. Currently, there is no standard treatment for pregnancy-induced leg cramps. The objective of this study was to evaluate the therapeutic efficacy of oral magnesium in pregnant women with leg cramps. This double-blinded, randomised, placebo-controlled trial included 86 healthy pregnant women, 14-34 weeks of gestation who had leg cramps at least twice per week. The study period was 4 weeks. Eighty women completed the study. Forty-one women were assigned to magnesium bisglycinate chelate (300 mg per day) and 39 women to placebo. Details of leg cramps were recorded before beginning the treatment and the fourth week of study. Outcome measure was the reduction of cramp frequency after treatment and cramp intensity measured by 100-mm visual analogue scale. Fifty per cent reduction of cramp frequency was significantly higher in the magnesium group than the placebo group (86.0% vs. 60.5%, P=0.007). The 50% reduction of cramp intensity was also significantly higher in the treatment group than in the placebo group (69.8% vs. 48.8%, P=0.048). There were no significant differences between the two groups in terms of side effects such as nausea and diarrhoea. These results demonstrated that oral magnesium supplement can improve the frequency and intensity of pregnancy-induced leg cramps. Therefore, oral magnesium may be a treatment option for women suffering from pregnancy-induced leg cramps.