Most low- and middle-income countries present suboptimal intakes of
calcium during pregnancy and high rates of mortality due to maternal hypertensive disorders.
Calcium supplementation during pregnancy is known to reduce the risk of these disorders and associated complications, including
preeclampsia, maternal morbidity, and
preterm birth, and is, therefore, a recommended intervention for pregnant women in populations with low
dietary calcium intake (e.g., where ≥25% of individuals in the population have intakes less than 800 mg
calcium/day). However, this intervention is not widely implemented in part due to cost and logistical issues related to the large dose and burdensome dosing schedule (three to four 500-mg doses/day). WHO recommends 1.5-2 g/day but limited evidence suggests that less than 1 g/day may be sufficient and ongoing trials with low-dose
calcium supplementation (500 mg/day) may point a path toward simplifying supplementation regimens.
Calcium carbonate is likely to be the most cost-effective choice, and it is not necessary to counsel women to take
calcium supplements separately from
iron-containing supplements. In populations at highest risk for
preeclampsia, a combination of
calcium supplementation and food-based approaches, such as food fortification with
calcium, may be required to improve
calcium intakes before pregnancy and in early gestation.