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Preterm Birth

Overview

Preterm birth, which is defined by the WHO as live birth occurring before 37 weeks of pregnancy, can be triggered by hypertensive (high blood pressure) disorders during pregnancy, including preeclampsia, and remains a leading cause of neonatal mortality worldwide—particularly in low-income countries where calcium availability and intake is often insufficient. Research demonstrates that calcium supplementation during pregnancy can reduce preterm birth risk by approximately 24%, representing a significant opportunity for intervention.

Lancet Estimates
Global Burden of Disease Estimates

Data Source

This visualization presents two different modeled estimates of preterm birth: 1) the 2020 estimates published in The Lancet, which is reported as the incidence rate per 100 live births; and 2) the 2021 Global Burden of Disease study conducted by the Institute for Health Metrics and Evaluation (IHME), which is quantified in disability-adjusted life years (DALYs) per 100,000.

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Strategic Applications

This map serves as a valuable planning tool for identifying regions where calcium interventions could potentially improve preterm birth outcomes. For maximum impact, this data should be analyzed alongside preeclampsia prevalence and calcium intake maps—as areas exhibiting the combination of high preterm birth rates, elevated preeclampsia incidence, and low calcium consumption represent priority targets for public health initiatives.

Further Reading

  • Ohuma, E. O., Moller, A. B., Bradley, E., Chakwera, S., Hussain-Alkhateeb, L., Lewin, A., … & Moran, A. C. (2023). National, regional, and global estimates of preterm birth in 2020, with trends from 2010: a systematic analysis. The Lancet, 402(10409), 1261-1271. View article
  • Institute for Health Metrics and Evaluation (IHME). GBD Compare Data Visualization. Global Burden of Disease (GBD) Study 2021. Seattle, WA: IHME, University of Washington, 2023. Access interactive data
  • Hofmeyr, G. J., Lawrie, T. A., Atallah, Á. N., & Torloni, M. R. (2018). Calcium supplementation during pregnancy for preventing hypertensive disorders and related problems. Cochrane Database of Systematic Reviews, (10). View article
  • Gomes, F., Ashorn, P., Askari, S., Belizan, J. M., Boy, E., Cormick, G., … & Bourassa, M. W. (2022). Calcium supplementation for the prevention of hypertensive disorders of pregnancy: current evidence and programmatic considerations. Annals of the New York Academy of Sciences, 1510(1), 52-67. View article

Last updated: 8/1/25