Calcium supplementation for the prevention of pre-eclampsia: Challenging the evidence from meta-analyses

source extracted confidence: high 2026-04-09
#female #humans #pregnancy #calcium #dietary-supplements

Calcium supplementation for the prevention of pre-eclampsia: Challenging the evidence from meta-analyses

Wright et al., 2024 | BJOG | Meta Analysis

Citation

Wright David, Wright Alan, ... Nicolaides Kypros H. Calcium supplementation for the prevention of pre-eclampsia: Challenging the evidence from meta-analyses. BJOG. 2024-Oct;131(11):1524-1529. doi:10.1111/1471-0528.17769

Abstract

OBJECTIVE: To investigate the validity of the conclusion from Cochrane reviews and meta-analyses that treatment with calcium supplementation during pregnancy reduces the risk for pre-eclampsia by 55%, which has been influential in international guidelines and future research. DESIGN: Sensitivity analysis of data from Cochrane reviews of trials evaluating high-dose calcium supplementation (of at least 1 g/day) for reduction of pre-eclampsia risk. SETTING: Systematic review and meta-analysis. POPULATION: The Cochrane reviews and meta-analyses included 13 trials enrolling a total of 15 730 women. Random-effects meta-analysis of these studies resulted in a mean risk ratio (RR, calcium/placebo) of 0.45 (95% confidence interval [CI] 0.31-0.65; p < 0.0001). METHODS: We carried out a sensitivity analysis of evidence from the relevant Cochrane review, to examine the impact of study size. MAIN OUTCOME MEASURES: pre-eclampsia. RESULTS: In the three largest studies, accounting for 13 815 (88%) of total recruitment, mean RR was 0.92 (95% CI 0.80-1.06) and there was no evidence of heterogeneity between studies (I2 = 0). With inclusion of the smaller studies, mean RR decreased to 0.45 and I2 increased to 70%. CONCLUSIONS: In assessment of the effect of calcium supplementation on pre-eclampsia risk, the naive focus on the mean of the random-effects meta-analysis in the presence of substantial heterogeneity is highly misleading.

Key Findings

In the three largest studies, accounting for 13 815 (88%) of total recruitment, mean RR was 0.92 (95% CI 0.80-1.06) and there was no evidence of heterogeneity between studies (I2 = 0). With inclusion of the smaller studies, mean RR decreased to 0.45 and I2 increased to 70%.

Outcomes Measured

  • Requires manual extraction

Population

Field Value
Population See abstract
Sample Size 13
Age Range See abstract
Condition See abstract

MeSH Terms

  • Female
  • Humans
  • Pregnancy
  • Calcium
  • Dietary Supplements
  • Meta-Analysis as Topic
  • Pre-Eclampsia

Evidence Classification

  • Level: Meta Analysis
  • Publication Types: Journal Article, Meta-Analysis, Systematic Review
  • Vertical: calcium

Provenance

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