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Evidence-Based Supplement Research
Evidence-Based Supplement Research

The Efficacy of Zinc Supplementation Alone or in Combination for Improving Pregnancy and Infant Outcomes: A Systematic Review and Meta-Analysis.

  • 2025-08-20
  • Journal of evidence-based medicine 18(3)
    • Sha Diao
    • Yuan Feng
    • Xue Peng
    • Dan Liu
    • Liang Huang
    • Linan Zeng
    • Lingli Zhang

Study Design

Type
Meta-Analysis
Population
healthy pregnant women
Methods
Systematic review of six databases through March 27, 2025 for randomized controlled trials (RCTs) on prenatal zinc supplementation

Objective

To evaluate zinc supplementation's efficacy in pregnancy, addressing gaps in previous reviews regarding high-risk subgroups and combination therapies.

Methods

Systematic review of six databases through March 27, 2025 for randomized controlled trials (RCTs) on prenatal zinc supplementation. Risk of bias was assessed using the Cochrane Risk of Bias 2. Stratified analyses was conducted by participant or intervention characteristics, with meta-analysis or qualitative synthesis when appropriate. Sensitivity analyses was conducted by excluding studies with high risk of bias. The systematic review was registered in PROSPERO (CRD42023440314).

Results

77 RCTs were included. Compared with no zinc, zinc monotherapy among healthy pregnant women resulted in higher serum zinc level (standard mean difference (SMD) the second trimester = 0.32, 95% confidence interval (CI) 0.20 to 0.44; SMDthe third trimester = 0.51, 95% CI 0.27 to 0.76), lower fetal intrauterine retardation rate (risk ratio = 0.23, 95% CI 0.16 to 0.35), longer neonatal birth length (SMD = 0.66, 95% CI 0.21 to 1.12), bigger birth head circumference (SMD = 0.58, 95% CI 0.08 to 1.09), higher 1-min Apgar score (SMD = 0.28, 95% CI 0.06 to 0.49) and cord blood zinc level (SMD = 0.36, 95% CI 0.17 to 0.56). No additional benefits observed with zinc-iron-folate combinations versus iron-folate alone. Qualitative synthesis of limited evidence suggested potential benefits for high-risk groups (anemia, gestational diabetes, zinc deficiency or impaired intravenous glucose tolerance test).

Conclusions

Zinc monotherapy may benefit healthy pregnancies and high-risk groups, but combination regimens show no additional advantages. Further research should confirm these findings.

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