Oral magnesium supplementation for leg cramps in pregnancy—An observational controlled trial

Background
Oral magnesium for leg cramps treatment in pregnancy is a controversial issue according to recent Cochrane systematic review. This study aims to evaluate the efficacy of Mg++ supplementation in leg cramps treatment in pregnancy.
Methods
This observational clinical trial studied 132 pregnant women with leg cramps in the first trimester of pregnancy. At baseline, 74 (56.3%) had two leg cramps episodes per week, 28 (21.1%) three episodes, 13 (9.8%) four episodes and 9 (6.8%) five or more episodes. They were randomized 1:1 to 300 mg/day of oral Mg++ citrate (n = 66) or placebo (n = 66). The primary outcome was the frequency of leg cramps episodes per week reported by pregnant women. Secondary outcomes were the ocurrence of leg cramps and oral magnesium side effects.
Results
130 pregnant women completed the study and the two groups were comparable according to some sociodemographic and clinical characteristics. After 4 weeks of intervention it was observed a 28.4% (39/132) (CI 95%: 20.9–37.0) reduction of leg cramps in all participants and no difference between the two groups was found; reduction of 27.2% (18/66) (CI 95%: 17.0–39.6) in Mg++ group and 32.8% (21/66) (CI 95%: 21.6–45.7) in the placebo group. The OR of leg cramps was 1.3 (CI 95%: 0.6–2.9), p = 0.527, taking the placebo group as reference. Among pregnant women who remained with leg cramps the mean of leg cramps episodes per week showed no significance difference between the Mg++ and placebo groups; t-student test: p = 0.408. Four pregnant women showed gastrointestinal side effects; 2 in each group had nauseas and diarrhoea.
Conclusion
Oral magnesium supplementation during pregnancy did not reduce the ocurrence and frequency of episodes of leg cramps.

背景
根据近期考克兰系统综述（Cochrane Systematic Review），孕期腿部痉挛治疗使用口服镁剂尚存争议。本研究旨在评估镁离子（Mg²+）补充疗法用于孕期腿部痉挛治疗的有效性。

方法
本观察性临床试验纳入132名孕早期出现腿部痉挛的孕妇。基线时，74例（56.3%）每周腿部痉挛发作2次，28例（21.1%）发作3次，13例（9.8%）发作4次，9例（6.8%）发作5次及以上。研究对象以1:1比例随机分为两组，分别每日口服300mg柠檬酸镁（n=66）或安慰剂（placebo，n=66）。本研究的主要结局指标为孕妇自述的每周腿部痉挛发作频率；次要结局指标为腿部痉挛发作情况及口服镁剂的不良反应发生情况。

结果
共有130名孕妇完成本研究，两组在部分社会人口学及临床特征上具有可比性。干预4周后，所有受试者的腿部痉挛发作频率降低28.4%（39/132），95%置信区间（Confidence Interval, CI）为20.9–37.0，且两组间无显著差异；其中镁剂组发作频率降低27.2%（18/66），95%置信区间（CI）为17.0–39.6，安慰剂组降低32.8%（21/66），95%置信区间（CI）为21.6–45.7。以安慰剂组为参照，腿部痉挛发作的优势比（Odds Ratio, OR）为1.3（95%CI：0.6–2.9），p=0.527。在仍存在腿部痉挛的孕妇中，镁剂组与安慰剂组的每周腿部痉挛发作次数均值无显著差异，t检验结果为p=0.408。共有4名孕妇出现胃肠道不良反应，两组各有2名孕妇分别出现恶心与腹泻。

结论
孕期口服镁剂补充治疗并未降低腿部痉挛的发作发生率与频率。