Ota Erika, Mori Rintaro, Middleton Philippa, Tobe-Gai Ruoyan, Mahomed Kassam, Miyazaki Celine, Bhutta Zulfiqar A
Department of Health Policy, National Center for Child Health and Development, 2-10-1 Okura, Setagaya-ku, Tokyo, Japan, 157-8535.
Cochrane Database Syst Rev. 2015 Feb 2;2015(2):CD000230. doi: 10.1002/14651858.CD000230.pub5.
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.
To assess the effects of zinc supplementation in pregnancy on maternal, fetal, neonatal and infant outcomes.
We searched the Cochrane Pregnancy and Childbirth Group's Trials Register (31 October 2014) and reference lists of retrieved studies.
Randomised trials of zinc supplementation in pregnancy. We excluded quasi-randomised controlled trials.
Three review authors applied the study selection criteria, assessed trial quality and extracted data. When necessary, we contacted study authors for additional information. The quality of the evidence was assessed using GRADE.
We included 21 randomised controlled trials (RCTs) reported in 54 papers involving over 17,000 women and their babies. One trial did not contribute data. Trials were generally at low risk of bias. Zinc supplementation resulted in a small reduction in preterm birth (risk ratio (RR) 0.86, 95% confidence interval (CI) 0.76 to 0.97 in 16 RCTs; 16 trials of 7637 women). This was not accompanied by a similar reduction in numbers of babies with low birthweight (RR 0.93, 95% CI 0.78 to 1.12; 14 trials of 5643 women). No clear differences were seen between the zinc and no zinc groups for any of the other primary maternal or neonatal outcomes, except 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. The GRADE quality of the evidence was moderate for preterm birth, small-for-gestational age, and low birthweight, and low for stillbirth or neonatal death and birthweight.
AUTHORS' CONCLUSIONS: The evidence for a 14% relative reduction in preterm birth for zinc compared with placebo was primarily represented by trials 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.
有人提出，血清锌水平低可能与妊娠结局不佳有关，如产程延长、宫缩乏力性产后出血、妊娠高血压、早产和过期妊娠，尽管其中许多关联尚未得到证实。
评估孕期补充锌对孕产妇、胎儿、新生儿和婴儿结局的影响。
我们检索了Cochrane妊娠与分娩组试验注册库（2014年10月31日）以及检索到的研究的参考文献列表。
孕期补充锌的随机试验。我们排除了半随机对照试验。
三位综述作者应用研究选择标准，评估试验质量并提取数据。必要时，我们联系研究作者以获取更多信息。使用GRADE评估证据质量。
我们纳入了54篇论文中报告的21项随机对照试验（RCT），涉及超过17000名妇女及其婴儿。一项试验未提供数据。试验一般偏倚风险较低。补充锌使早产略有减少（16项RCT的风险比（RR）为0.86，95%置信区间（CI）为0.76至0.97；7637名妇女的16项试验）。但低出生体重儿数量没有类似减少（RR为0.93，95%CI为0.78至1.12；5643名妇女的14项试验）。除一项试验中的引产情况外，锌组和非锌组在任何其他主要孕产妇或新生儿结局方面均未观察到明显差异。在锌水平低与正常以及营养水平低与正常的女性亚组中，或在依从治疗与不依从治疗的女性中，均未发现明显不同的模式。早产、小于胎龄儿和低出生体重的证据质量为中等，死产或新生儿死亡以及出生体重的证据质量为低等。
与安慰剂相比，锌使早产相对减少14%的证据主要来自涉及低收入女性的试验，这在围产期死亡率高的地区有一定相关性。没有令人信服的证据表明孕期补充锌会带来其他有用且重要的益处。由于早产关联很可能反映了营养状况差，因此应将研究重点放在改善贫困地区人群总体营养状况的方法上，而不是孤立地关注微量营养素和/或锌补充，这应是当务之急。
