Imdad et al. BMC Public Health 2011, 11(Suppl 3):S18 http://www.biomedcentral.com/1471-2458/11/S3/S18 poor compliance were considered as few of the major barriers in implementation of these programs in these countries [53]. Issues of cost effectiveness should also be considered and weighed for increasing the calcium intake by dietary modification or food fortification. Increasing dietary calcium intake may seem to be an easier intervention than calcium supplementation, although availability of dairy products in many coun- tries may not be sufficient to fulfill the need. Alterna- tively, targeted food fortification with calcium may be a feasible intervention, especially for high-risk women, who may not be targeted for individual calcium sup- plementation because they do not come for antenatal care services [54]. Conclusion Calcium supplementation during pregnancy leads to a reduction of 59 % (95 % CI 31 % to 76 %) in risk of pre-eclampsia, 45 % (95 % CI 15 % to 64 %) in risk of development of gestational hypertension and 12 % (95 % CI 1% to 22 %) in risk of preterm birth in developing countries. Calcium should be supplemented to all women during pregnancy in developing countries. Additional material Additional File 1: Quality assessment of calcium supplementation during pregnancy on maternal and neonatal outcomes Acknowledgment This work was supported in part by a grant to the US Fund for UNICEF from the Bill & Melinda Gates Foundation (grant 43386) to “Promote evidence- based decision making in designing maternal, neonatal and child health interventions in low- and middle-income countries”. We thank Dr Mohammad Yawar Yakoob for critically reviewing the manuscript. This article has been published as part of BMC Public Health Volume 11 Supplement 3, 2011: Technical inputs, enhancements and applications of the Lives Saved Tool (LiST). The full contents of the supplement are available online at http://www.biomedcentral.com/1471-2458/11?issue=S3. Authors’ contributions Professor Zulfiqar A Bhutta conceived the idea and secured support for the review. Dr Aamer Imdad and Dr Afshan Jabeen undertook the literature search, data extraction and wrote the manuscript under the supervision of Professor Bhutta. Competing interests We do not have any financial or non-financial competing interests for this review. Published: 13 April 2011 References 1. Duley L: The global impact of pre-eclampsia and eclampsia. Semin Perinatol 2009, 33(3):130-137. 2. Khan KS, Wojdyla D, Say L, Gulmezoglu AM, Van Look PF: WHO analysis of causes of maternal death: a systematic review. Lancet 2006, 367(9516):1066-1074. 3. Villar J, Say L, Shennan A, Lindheimer M, Duley L, Conde-Agudelo A: Methodological and technical issues related to the diagnosis, screening, Page 12 of 13 prevention and treatment of pre-eclampsia and eclampsia. International Journal of Gynecology & Obstetrics 2004, 85(Suppl 1):S28-S41. 4. Villar J, Belizan J, Fisher P: Epidemiological observation on the realtionship between calcium intake and eclampsia. Int J Gynaecol Obstet 1983, 21:271. 5. Habli M, Levine RJ, Qian C, Sibai B: Neonatal outcomes in pregnancies with preeclampsia or gestational hypertension and in normotensive pregnancies that delivered at 35, 36, or 37 weeks of gestation. Am J Obstet Gynecol 2007, 197(4):406 e401-407. 6. Ananth CV, Basso O: Impact of pregnancy-induced hypertension on stillbirth and neonatal mortality. Epidemiology 2010, 21(1):118-123. 7. Ortega RM, Martinez RM, Lopez-Sobaler AM, Andres P, Quintas ME: Influence of calcium intake on gestational hypertension. Ann Nutr Metab 1999, 43(1):37-46. 8. Hofmeyr GJ, Duley L, Atallah A: Dietary calcium supplementation for prevention of pre-eclampsia and related problems: a systematic review and commentary. Bjog 2007, 114(8):933-943. 9. Bucher HC, Cook RJ, Guyatt GH, Lang JD, Cook DJ, Hatala R, Hunt DL: Effects of dietary calcium supplementation on blood pressure. A meta- analysis of randomized controlled trials. Jama 1996, 275(13):1016-1022. 10. Hofmeyr GJ, Atallah AN, Duley L: Calcium supplementation during pregnancy for preventing hypertensive disorders and related problems. Cochrane Database Syst Rev 2006, 3:CD001059. 11. Trumbo PR, Ellwood KC: Supplemental calcium and risk reduction of hypertension, pregnancy-induced hypertension, and preeclampsia: an evidence-based review by the US Food and Drug Administration. Nutr Rev 2007, 65(2):78-87. 12. Walker N, Fischer-Walker C, Bryce J, Bahl R, Cousens S: Standards for CHERG reviews of intervention effects on child survival. Int J Epidemiol 39(Suppl 1):i21-31. 13. Atkins D, Eccles M, Flottorp S, Guyatt GH, Henry D, Hill S, Liberati A, O’Connell D, Oxman AD, Phillips B, et al: Systems for grading the quality of evidence and the strength of recommendations I: critical appraisal of existing approaches The GRADE Working Group. BMC Health Serv Res 2004, 4(1):38. 14. Worlbank: WorldBank. Data - Country Classification. 2008. 2008 [http:// web.worldbank.org/]. 15. ACOG practice bulletin. Diagnosis and management of preeclampsia and eclampsia. Number 33, January 2002. Obstet Gynecol 2002, 99(1):159-167. 16. Cochrane Handbook for Systematic Reviews of Interventions. Higgins JPT, Green S 2008 [http://www.cochrane-handbook.org], Version 5.0.2 [updated September 2009]. 17. RevMan: The Cochrane Colloboration. Review Manager (RevMan) 5 for Windows. Oxford England; 2003. 18. Almirante CY: Calcium supplementation during pregnancy in the prevention of EPH gestosis. Prenatal and Neonatal Medicine 1998, 3(suppl):1-24. 19. Felix C, Jacome P, Lopez A, Moya W, Narvaez M, Lopez-Jaramillo P: The hypotensive effect of calcium supplementation during normal pregnancy in Andean women is not related to vascular production of prostacyclin by umbilical arteries. Journal of Obstetrics and Gynaecology 1991, 11(2):93-96. 20. Knight KB, Keith RE: Calcium supplementation on normotensive and hypertensive pregnant women. Am J Clin Nutr 1992, 55(4):891-895. 21. Marya RK, Rathee S, Manrow M: Effect of calcium and vitamin D supplementation on toxaemia of pregnancy. Gynecol Obstet Invest 1987, 24(1):38-42. 22. Repke J, Villar J, Bergel E, Belizan JM: The effect of iron absorption in patients receiving calcium supplementation. 9th Annual Meeting of the Society of Perinatal Obstetricians New Orleans, Louisiana, USA; 1989. 23. Montanaro D, Boscutti G, Antonucci F, Messa P, Mioni G, Driul P: Prevention of pregnancy-induced hypertension (PIH) and preeclampsia (PE) by oral calcium supplementation. Proceedings of the 10th International Congress of Nephrology London UK; 1987, 281. 24. Raman L, Rajalakshmi K, Krishnamachari KA, Sastry JG: Effect of calcium supplementation to undernourished mothers during pregnancy on the bone density of the bone density of the neonates. Am J Clin Nutr 1978, 31(3):466-469. 25. Boggess KA, Samuel L, Schmucker BC, Waters J, Easterling TR: A randomized controlled trial of the effect of third-trimester calcium