Low-dose calcium supplementation may reduce the risk of preeclampsia
Although epidemiological studies have linked low dietary calcium intake with preeclampsia, current guidelines recommend supplementation with 1.5–2 g/day, which may be risky as this level of supplementation exceeds the recommended daily allowance of 1–1.3 g/day. However, a recent systematic review suggests that supplementation with lower doses of calcium (<1 g/day) may be sufficient to reduce the risk.
The investigators searched PubMed and the Cochrane Pregnancy and Childbirth Group trials register, and identified nine eligible trials that assessed the effects of supplementation with low-dose calcium, either alone or in combination with other supplements. Collectively, these involved 2,234 women.
The relative risk (RR) of preeclampsia was consistently reduced with low-dose calcium supplementation, irrespective of whether this was alone or in combination with other supplements (RR 0.38, 95% confidence interval [CI] 0.28–0.52). Subgroup analyses supported this finding, including the analyses for low-dose calcium alone (RR 0.36, 95% CI 0.23–0.57) or in combination with linoleic acid (RR 0.23, 95% CI 0.09–0.60) or vitamin D (RR 0.49, 0.31–0.78). A trend towards a reduced risk was also observed for the combination of low-dose calcium and antioxidants (RR 0.24, 95% CI 0.06–1.01).
The researchers concluded that further randomised controlled trials are required to confirm these findings, which could have global implications and may change current guideline recommendations.