Pre-eclampsia is a common cause of morbidity and mortality in pregnancy. Preterm birth is often caused by high blood pressure. This systematic review (Cohrane database) found that calcium supplementation during pregnancy may reduce the risk of pre-eclampsia, hypertension and pre-term birth in women at risk. Those with low baseline calcium intake may benefit most.
Calcium supplements increase risk of myocardial infarctions
Sufficient intake of calcium is essential for bone health. High dietary intake of calcium is associated with decreased incidence of cardiovasular events in observational studies. Recently some randomized controlled trials show that calcium supplements may worsen cardiovasular health in renal failure. This meta-analysis of randomized controlled trials (British Medical Journal), shows that use of calcium supplements may increase risk of myocardial infarctions in other populations as well.