Zinc supplementation for improving pregnancy and infant outcome

source extracted confidence: high 2026-04-09
#dietary-supplements #female #humans #infant-low-birth-weight #infant-newborn

Zinc supplementation for improving pregnancy and infant outcome

Mori et al., 2012 | Cochrane Database Syst Rev | Meta Analysis

Citation

Mori Rintaro, Ota Erika, ... Bhutta Zulfiqar A. Zinc supplementation for improving pregnancy and infant outcome. Cochrane Database Syst Rev. 2012-Jul-11(7):CD000230. doi:10.1002/14651858.CD000230.pub4

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 (30 September 2011) and reference lists of retrieved studies. SELECTION CRITERIA: Randomised trials of zinc supplementation in pregnancy. We excluded quasi-randomised controlled trials. DATA COLLECTION AND ANALYSIS: Three review authors applied the study selection criteria, assessed trial quality and extracted data. When necessary, we contacted study authors for additional information. MAIN RESULTS: We included 20 randomised controlled trials (RCTs) reported in 51 papers involving over 15,000 women and their babies. Trials were generally at low risk of bias. Zinc supplementation resulted in a small but significant 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 significant 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. 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.

Key Findings

We included 20 randomised controlled trials (RCTs) reported in 51 papers involving over 15,000 women and their babies. Trials were generally at low risk of bias. Zinc supplementation resulted in a small but significant 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 s

Outcomes Measured

  • Requires manual extraction

Population

Field Value
Population See abstract
Sample Size 20
Age Range See abstract
Condition hypertension

MeSH Terms

  • Dietary Supplements
  • Female
  • Humans
  • Infant, Low Birth Weight
  • Infant, Newborn
  • Pregnancy
  • Pregnancy Outcome
  • Premature Birth
  • Randomized Controlled Trials as Topic
  • Zinc

Evidence Classification

  • Level: Meta Analysis
  • Publication Types: Journal Article, Meta-Analysis, Research Support, Non-U.S. Gov't, Systematic Review
  • Vertical: cochrane-supplements

Provenance

Source extracted via PubMed E-utilities API on 2026-04-09