Department of Epidemiology and Biostatistics, School of Public Health-Bloomington, Indiana University, Bloomington, Indiana, USA.
Department of Obstetrics and Gynecology, Columbia University Irving Medical Center, New York, New York, USA.
Nutr Rev. 2021 Jan 9;79(2):188-199. doi: 10.1093/nutrit/nuaa028.
Experimental studies suggest that magnesium levels in pregnant women may affect the length of gestation, as magnesium affects the activity of smooth muscle in the uterus. Little is known about the association between magnesium levels or supplementation and the rate of preterm birth.
The aim of this systematic review was to summarize the data on magnesium soil levels and preterm birth rates from ecological, observational, and interventional studies.
Soil magnesium levels were obtained from US Geological Survey data, and preterm birth rates were acquired from the March of Dimes Foundation. Relevant epidemiological and clinical studies published until April 2019 in peer-reviewed journals were retrieved from PubMed, Google Scholar, and related reference lists.
Original studies published in English, conducted in humans, and in which magnesium (dietary/supplemental intake or biomarkers) was an exposure and preterm birth was an outcome were included.
Eleven studies were included in the systematic review. Meta-analysis was performed on 6 studies. Overall relative risk (RR) and corresponding 95%CIs for risk of preterm birth in relation to magnesium supplementation were estimated by a random-effects model.
The ecological study revealed an inverse correlation between magnesium content in soil and rates of preterm birth across the United States (r = -0.68; P < 0.001). Findings from 11 observational studies generally support an inverse association between serum magnesium levels and rates of preterm birth. Of the 6 eligible randomized controlled trials, which included 3068 pregnant women aged 20 to 35 years and 352 preterm infants, the pooled RR was 0.58 (95%CI, 0.35-0.96) for women in the magnesium supplementation group compared with women in the control group.
Accumulated evidence from ecological, observational, and interventional studies consistently indicates that adequate magnesium intake during pregnancy may help reduce the incidence of preterm birth.
实验研究表明，孕妇体内的镁含量可能会影响妊娠期的长短，因为镁会影响子宫平滑肌的活动。目前人们对镁含量或补充剂与早产率之间的关系知之甚少。
本系统评价旨在总结关于土壤镁含量与早产率的生态、观察性和干预性研究数据。
土壤镁含量来自美国地质调查局的数据，早产率来自美国家庭健康协会。从 PubMed、Google Scholar 和相关参考文献中检索到截至 2019 年 4 月发表在同行评议期刊上的相关流行病学和临床研究。
纳入发表在英文期刊上、以人为研究对象、以镁（饮食/补充摄入或生物标志物）为暴露因素、以早产为结局的原始研究。
系统评价纳入了 11 项研究。对 6 项研究进行了荟萃分析。采用随机效应模型，估计了镁补充与早产风险之间的总体相对风险（RR）及其相应的 95%置信区间（CI）。
美国的一项生态研究表明，土壤中镁含量与早产率之间呈负相关（r=-0.68；P<0.001）。11 项观察性研究的结果普遍支持血清镁水平与早产率之间呈负相关。在 6 项合格的随机对照试验中，包括 3068 名年龄在 20 至 35 岁的孕妇和 352 名早产儿，与对照组相比，镁补充组的孕妇发生早产的汇总 RR 为 0.58（95%CI，0.35-0.96）。
生态、观察性和干预性研究的累积证据一致表明，孕妇在妊娠期间摄入足够的镁可能有助于降低早产的发生率。
