Non-inferiority of Lower Dose Calcium Supplementation During Pregnancy

The World Health Organization currently recommends that pregnant women in populations with low calcium intake receive daily calcium supplementation (1500 - 2000 mg) divided into three doses which are preferably taken at mealtimes, in addition to daily iron folic-acid supplements. Despite proven efficacy and the WHO recommendation, calcium supplementation in pregnancy is not standard of care in the vast majority of low-income and middle-income countries. Two important barriers to implementation are the cost of the supplements and complexity of the suggested calcium dosing schedule. A lower dose of calcium (500 mg) administered as a single dose has been shown to be beneficial in several trials, and if found to be as effective as the 1500 mg supplementation regimen, it may help overcome these barriers and increase individual and health system adoption.

The Investigators will conduct two parallel, individually randomized, double blind non-inferiority trials in India and Tanzania. Participating pregnant woman will be randomized to either 1500 mg or 500 mg calcium supplementation. The India and Tanzania trials are independently powered for the primary outcomes of i) preeclampsia and ii) preterm birth. The India and Tanzania sites will each enroll 11,000 participants.