Calcium Supplementation in Pregnancy and Hypertensive Disorder Prevention

Calcium supplementation during pregnancy has emerged as a cost-effective strategy to mitigate the global burden of hypertensive disorders, particularly pre-eclampsia and gestational hypertension. Low dietary calcium intake is common in many low- and middle-income countries, and observational studies have consistently shown an inverse relationship between maternal calcium levels and the risk of hypertensive complications. Supplementation is thought to stabilise vascular smooth muscle tone by modulating parathyroid hormone and intracellular calcium concentrations, thereby preventing vasoconstriction. Programmatic delivery through antenatal care platforms has demonstrated high acceptability and compliance when women receive clear dosing instructions alongside routine iron and folate. Although most trials initiate supplementation in the second half of pregnancy, emerging evidence explores preconception and early-gestation interventions. Global guidelines now recommend 1.5–2 g of elemental calcium daily for women with low dietary intake, with the aim of reducing maternal morbidity, perinatal mortality and long-term cardiovascular risk.

Research from Nature Portfolio

Recent studies have investigated the interplay between serum electrolytes and pregnancy blood pressure in diverse settings. In a 2023 cohort of over 1,000 women in late gestation, researchers measured ionised and total calcium alongside other key electrolytes. They found that women with ionised hypercalcaemia had substantially lower odds of developing hypertension, while those with total hypocalcaemia were at nearly double the risk of elevated blood pressure. These findings underscore the importance of maintaining adequate calcium homeostasis in late pregnancy and support routine biochemical monitoring as an adjunct to supplementation programmes.

Calcium Supplementation in Pregnancy and Hypertensive Disorder Prevention publication trend

The graph below shows the total number of articles in calcium supplementation in pregnancy and hypertensive disorder prevention across all publications each year (not limited to Nature Index journals).

Technical terms

Pre-eclampsia: A multisystem disorder of pregnancy characterised by new-onset hypertension and proteinuria after 20 weeks’ gestation.
Ionised calcium: The physiologically active fraction of serum calcium that is not bound to proteins.
Gestational hypertension: New-onset elevated blood pressure (≥140/90 mmHg) after 20 weeks’ gestation without significant proteinuria.
Randomised controlled trial: An experimental design in which participants are randomly allocated to receive either the intervention under study or a control, to assess efficacy objectively.

References

1. Association of hypertension in pregnancy with serum electrolyte disorders in late pregnancy among Cameroonian women. Scientific Reports (2023).
2. Prepregnancy and early pregnancy calcium supplementation among women at high risk of pre-eclampsia: a multicentre, double-blind, randomised, placebo-controlled trial. The Lancet (2019).
3. Calcium and Vitamin D Supplementation for Prevention of Preeclampsia: A Systematic Review and Network Meta-Analysis. Nutrients (2017).
4. The association between daily 500 mg calcium supplementation and lower pregnancy-induced hypertension risk in Bangladesh. BMC Pregnancy and Childbirth (2018).
5. Coverage, compliance, acceptability and feasibility of a program to prevent pre-eclampsia and eclampsia through calcium supplementation for pregnant women: an operations research study in one district of Nepal. BMC Pregnancy and Childbirth (2016).