Zinc supplementation for improving pregnancy and infant outcome

  • Review
  • Intervention

Authors


Abstract

Background

It has been suggested that low serum zinc levels may be associated with suboptimal outcomes of pregnancy such as prolonged labour, atonic postpartum haemorrhage, pregnancy-induced hypertension, preterm labour and post-term pregnancies, although many of these associations have not yet been established.

Objectives

To assess the effects of zinc supplementation in pregnancy on maternal, fetal, neonatal and infant outcomes.

Search methods

We searched the Cochrane Pregnancy and Childbirth Group's Trials Register (February 2007). We updated this search on 1 July 2011 and added the results to the awaiting classification section of the review.

Selection criteria

Randomised or quasi-randomised trials of zinc supplementation in pregnancy.

Data collection and analysis

Two review authors applied the study selection criteria, assessed trial quality and extracted data. When necessary, study authors were contacted for additional information.

Main results

We included 17 randomised controlled trials (RCTs) involving over 9000 women and their babies. Zinc supplementation resulted in a small but significant reduction in preterm birth (relative risk (RR) 0.86, 95% confidence interval (CI) 0.76 to 0.98 in 13 RCTs; 6854 women). This was not accompanied by a similar reduction in numbers of babies with low birthweight (RR 1.05 95% CI 0.94 to 1.17; 11 studies of 4941 women). No significant differences were seen between the zinc and no zinc groups for any of the other primary maternal or neonatal outcomes, except for a small effect favouring zinc for caesarean section (four trials with high heterogeneity) and for induction of labour in a single trial. No differing patterns were evident in the subgroups of women with low versus normal zinc and nutrition levels or in women who complied with their treatment versus those who did not.

Authors' conclusions

The 14% relative reduction in preterm birth for zinc compared with placebo was primarily in the group of studies involving women of low income and this has some relevance in areas of high perinatal mortality. There was no convincing evidence that zinc supplementation during pregnancy results in other useful and important benefits. Since the preterm association could well reflect poor nutrition, studies to address ways of improving the overall nutritional status of populations in impoverished areas, rather than focusing on micronutrient and or zinc supplementation in isolation, should be an urgent priority.

[Note: The 18 citations in the awaiting classification section of the review may alter the conclusions of the review once assessed.]

摘要

背景

補充鋅來改善妊娠和胎兒的結果

低血鋅濃度可能與妊娠未達最好結果有關,譬如產程過長、子宮無力導致產後出血妊娠高血壓症、早產以及過期妊娠,雖然這些關聯性之中有許多項目都尚未被證實

目標

評估懷孕時補充鋅對母體、胎兒、新生兒以及嬰兒結果的影響

搜尋策略

我們搜尋了Cochrane Pregnancy and Childbirth Group's Trials Register(2007年2月)資料庫

選擇標準

隨機或準隨機試驗評估懷孕時補充補充鋅的效果

資料收集與分析

兩位作者提供篩選的準則、評估試驗的品質並擷取數據。 當有必要時,研究作者們會聯繫以取得額外的資訊

主要結論

我們收納了17個隨機對照試驗,樣本數超過9000位婦女和她們的小孩。 補充鋅會稍微但顯著地降低早產的機率(R .86,95% confidence interval (CI) 0.76 to 0.98 in 13 RCTs;6854位婦女)。 但低出生體重的嬰兒數量並沒有出現相仿的降低趨勢(R .05 95% CI 0.94 to 1.17,11個研究4941位婦女)。 對於任何其他主要的母親或新生兒結果,補充鋅和無鋅組之間則沒有顯著差異,除了補充鋅可能有利於剖腹產的結果(4個高異質性的試驗)以及單一組試驗所顯示補充鋅有利於引產的結果。在細分的次族群中,補充或不補充鋅的婦女,原本體內鋅含量是較低或正常以及營養狀況如何,似乎與結果並無顯著的差異

作者結論

這種與安慰劑比較下補充鋅可降低14% 早產機率的結果,主要是在針對低收入婦女所做的研究中出現,而這些族群與高周產期死亡率地區有關。 沒有具說服力的證據顯示,在懷孕期間補充鋅能獲得其它有用及重要的益處。 既然早產的關聯性能適切反應出營養不良的情況,研究鎖定探討如何改善赤貧地區人口的整體營養狀態,比單獨鎖定補充微量元素或鋅,應該更有迫切的優先權

翻譯人

此翻譯計畫由臺灣國家衛生研究院(National Health Research Institutes, Taiwan)統籌

總結

懷孕期間補充鋅能稍微協助降低早產的機率,但不會有助於預防其它的問題,譬如低出生體重嬰兒。 許多處於生產年齡的婦女可能會有輕微到中度的鋅缺乏現象。 低鋅濃度可能會導致早產或延長產程。 鋅缺乏也有可能會影響胎兒的生長。 本文的17個試驗,樣本數超過9000位婦女和她們的小孩。 雖然補充鋅對協助降低早產會有一點影響,但它不會有助於預防低出生體重嬰兒。 與其補充孕婦鋅,找出方法改善婦女全面性的營養狀態,特別是低收入地區,對改善母親和嬰兒的健康會更有用

Plain language summary

Zinc supplementation for improving pregnancy and infant outcome

Taking zinc during pregnancy helps to slightly reduce preterm births, but does not help prevent other problems such as low birthweight babies.

Many women of childbearing age may have mild to moderate zinc deficiency. Low zinc levels may cause preterm birth or they may prolong labour. It is also possible that zinc deficiency may affect infant growth as well. The review of 17 trials, involving over 9000 women and their babies, found that although zinc supplementation has a small effect on reducing preterm births, it does not help to prevent low birthweight babies. Finding ways to improve women's overall nutritional status, particularly in low-income areas, will do more to improve the health of mothers and babies than supplementing pregnant women with zinc.

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