Calcium for Pre-eclampsia Prevention: A Systematic Review and Network Meta-analysis to Guide Personalized Antenatal Care

( BJOG . 2022;129:1833–1843) Pre-eclampsia effects 2% to 5% of pregnancies. Health disparities are apparent with 99% of maternal pre-eclamptic deaths occurring in low- and middle-income countries (total deaths are between 30,000 and over 500,000 annually). A daily dose of aspirin (150 mg) has been shown to prevent 60% of preterm (<37 wk of gestation) pre-eclampsia, although it has not been shown to impact term pre-eclampsia (≥37 wk of gestation), accounting for over 70% of disease cases. Systematic reviews have shown that calcium supplementation can also decrease pre-eclampsia rates in parturient women [relative risk (RR) 0.45, 95% CI: 0.31-0.65] and decrease morbidity and preterm birth rates. The World Health Organization (WHO) has implemented a guideline of 1.5 to 2.0 g of calcium supplementation daily starting at 20 weeks of gestation for women not receiving adequate calcium through their diet. Questions remain regarding the appropriate calcium dose and which parturient women would benefit most from supplementation. This study aimed to determine the safety and effectiveness of calcium to help prevent pre-eclampsia, the optimal dosage amount (high dose of ≥1 g/d or low dose of <1 g/d), the optimal week of gestation that supplementation should commence, and which women would benefit the most from intervention.