Should women be advised to use calcium supplements during pregnancy? A decision analysis

Abstract

Adequate calcium intake during pregnancy is important in the prevention of pre-eclampsia. A substantial proportion of pregnant women do not meet the recommended daily calcium intake, even in developed countries. Nonetheless, calcium supplementation is not routinely advised to pregnant women in most countries. We aimed to predict the impact of advising pregnant women to use calcium supplements (1,000 mg/day) on the number of cases of pre-eclampsia prevented and related health care costs. By use of a decision-analytic model, we assessed the expected impact of advising calcium supplementation to either (1) all pregnant women, (2) women at high risk of developing pre-eclampsia, or (3) women with a low dietary calcium intake compared with current care. Calculations were performed for a hypothetical cohort of 100,000 pregnant women living in a high-income country, although input parameters of the model can be adjusted so as to fit other settings. The incidence of pre-eclampsia could be reduced by 25%, 8%, or 13% when advising calcium supplementation to all pregnant women, women at high risk of pre-eclampsia, or women with a low dietary calcium intake, respectively. Expected net financial benefits of the three scenarios were of €4,621,465, €2,059,165, or €2,822,115 per 100,000 pregnant women, respectively. Advising pregnant women to use calcium supplements can be expected to cause substantial reductions in the incidence of pre-eclampsia as well as related health care costs. It appears most efficient to advise calcium supplementation to all pregnant women, not subgroups only. KEYWORDScalcium supplementation, decision analysis, impact, pre-eclampsiaCalcium supplementation is a promising intervention for the prevention of pre-eclampsia (PE). A meta-analysis of 13 randomized controlled trials comprising 15,730 pregnant women, showed an overall reduction of 55% in the risk of PE among women receiving calcium supplements (>1,000 mg/day) from the second half of pregnancy to delivery as compared to women receiving placebo supplements (risk ratio (RR), 0.45; 95% confidence interval (95% CI), 0.31-0.65) (Hofmeyr, Lawrie, Atallah, Duley, & Torloni, 2014). The risk reduction was more pronounced among women with an increased risk of hypertensive disorders (RR 0.22, 95% CI 0.12-0.42, five trials) and among women with a low dietary calcium intake (mean intake <900 mg/day) (RR 0.36, 95% CI 0.20-0.65, eight trials).

The International Federation of Gynecology and Obstetrics (FIGO) initiative on pre‐eclampsia: A pragmatic guide for first‐trimester screening and prevention

“…A fourth cost‐effectiveness analysis focused on calcium prophylaxis and used a decision analytic model to examine the impact of this treatment if prescribed to all pregnant women, to women identified as being high risk for PE, or to women with low dietary intake of calcium . These three models led to corresponding reductions of disease prevalence of 25%, 8%, and 13%, respectively—all demonstrating cost savings ranging from €2 to 4.6 million per 100 000 pregnancies.…”

Dietary factors that affect the risk of pre-eclampsia

“…Meertens and colleagues used a decision analytical model to assess the cost-benefit of 1 g/day calcium supplementation from 20 weeks’ gestation to delivery 101. They determined that supplementing all pregnant women, as opposed to only those at heightened risk of pre-eclampsia or those with low dietary calcium intake, would have a greater impact on reducing incidence of pre-eclampsia and would be more cost-effective 101…”

Calcium intake from diet and supplement use during early pregnancy: the Expect study I

“…Because of the insufficient calcium content of most prenatal vitamins and multivitamins, it seems essential to advise the use of separate calcium supplements for pregnant women with an inadequate calcium intake. We recently showed that advising all pregnant women to use calcium supplements can be expected to cause substantial reductions in the incidence of preeclampsia as well as related health care costs [42]. No major side effects have been described, but the tolerable upper level of 2500 mg calcium per day should be taken into account, since hypercalcemia could cause renal insufficiency, vascular and soft-tissue calcification, hypercalciuria, and kidney stones [20,23].…”