Peña-Rosas Juan Pablo, Viteri Fernando E
Reduction of Micronutrient Malnutrition Unit, Department of Nutrition for Health and Development, World Health Organization, 20 Avenue Appia, Geneva 27, Switzerland, 1211.
Cochrane Database Syst Rev. 2009 Oct 7(4):CD004736. doi: 10.1002/14651858.CD004736.pub3.
Intake of supplements containing iron or a combination of iron and folic acid by pregnant women may improve maternal health and pregnancy outcomes. Recently, intermittent supplementation regimens have been proposed as alternatives to daily regimens.
To assess the effectiveness and safety of daily and intermittent use of iron or iron+folic acid supplements by pregnant women.
We searched the Cochrane Pregnancy and Childbirth Group's Trials Register (March 2009) and contacted relevant organisations for the identification of ongoing and unpublished studies.
All randomised or quasi-randomised trials evaluating the effect of supplementation with iron or iron+folic acid during pregnancy.
We assessed the methodological quality of trials using the standard Cochrane criteria. Two authors independently assessed which trials to include in the review and one author extracted data.
We included 49 trials, involving 23,200 pregnant women. Overall, the results showed significant heterogeneity across most prespecified outcomes and were analysed assuming random-effects. The trials provided limited information related to clinical maternal and infant outcomes.Overall, daily iron supplementation was associated with increased haemoglobin levels in maternal blood both before and after birth and reduced risk of anaemia at term. These effects did not differ significantly between women receiving intermittent or daily iron or iron+folic acid supplementation. Women who received daily prenatal iron supplementation with or without folic acid were less likely to have iron deficiency at term as defined by current cut-off values than those who received no treatment or placebo. Side effects and haemoconcentration (a haemoglobin level greater than 130 g/L) were more common among women who received daily iron or iron+folic acid supplementation than among those who received no treatment or placebo. The risk of haemoconcentration during the second and third trimester was higher among those on a daily regimen of iron supplementation. The clinical significance of haemoconcentration remains uncertain.
AUTHORS' CONCLUSIONS: Universal prenatal supplementation with iron or iron+folic acid provided either daily or weekly is effective to prevent anaemia and iron deficiency at term. We found no evidence, however, of the significant reduction in substantive maternal and neonatal adverse clinical outcomes (low birthweight, delayed development, preterm birth, infection, postpartum haemorrhage). Associated side effects and particularly haemoconcentration during pregnancy may suggest the need for revising iron doses and schemes of supplementation during pregnancy and adjust preventive iron supplementation recommendations.
孕妇摄入含铁或铁与叶酸组合的补充剂可能改善母体健康和妊娠结局。最近，间歇补充方案已被提议作为每日补充方案的替代方案。
评估孕妇每日和间歇使用铁或铁加叶酸补充剂的有效性和安全性。
我们检索了Cochrane妊娠与分娩组试验注册库（2009年3月），并联系了相关组织以识别正在进行和未发表的研究。
所有评估孕期补充铁或铁加叶酸效果的随机或半随机试验。
我们使用Cochrane标准评估试验的方法学质量。两位作者独立评估纳入综述的试验，一位作者提取数据。
我们纳入了49项试验，涉及23200名孕妇。总体而言，结果显示大多数预先设定的结局存在显著异质性，并采用随机效应模型进行分析。这些试验提供的与孕产妇和婴儿临床结局相关的信息有限。总体而言，每日补充铁与出生前后母体血液中血红蛋白水平升高以及足月时贫血风险降低相关。接受间歇或每日补充铁或铁加叶酸的女性之间，这些效果没有显著差异。与未接受治疗或安慰剂的女性相比，接受每日产前补充铁（无论是否含叶酸）的女性足月时按照当前临界值定义的缺铁可能性更小。接受每日补充铁或铁加叶酸的女性比未接受治疗或安慰剂的女性更常出现副作用和血液浓缩（血红蛋白水平大于130 g/L）。在每日补充铁方案的女性中，孕中期和孕晚期血液浓缩的风险更高。血液浓缩的临床意义仍不确定。
每日或每周普遍进行产前补充铁或铁加叶酸可有效预防足月时的贫血和缺铁。然而，我们没有发现实质性孕产妇和新生儿不良临床结局（低出生体重、发育迟缓、早产、感染、产后出血）显著减少的证据。相关的副作用，尤其是孕期的血液浓缩，可能表明需要修订孕期铁剂量和补充方案，并调整预防性铁补充建议。
