A recent study conducted by researchers from St. John’s Research Institute and Medical College, India challenges the World Health Organisation’s (WHO) calcium supplementation recommendations for preventing preeclampsia in pregnant women.
The study, titled ‘Two Randomised Trials of Low-Dose Calcium Supplementation in Pregnancy,’ was published in The New England Journal of Medicine and involved 11,000 nulliparous pregnant women across two independent trials in Bengaluru, India, and Dar es Salaam, Tanzania.
The WHO currently recommends a daily calcium intake of 1500–2000 mg during pregnancy, divided into three doses, to reduce the risk of preeclampsia, a hypertensive disorder affecting 2–8% of pregnancies and contributing to 45,000 maternal deaths annually.
However, the complexity comes in dosing scheme, which led to implementation barriers. This new study suggests that a lower dose of 500 mg/day could be equally effective in preventing preeclampsia, simplifying the supplementation regimen.
Dr. Pratibha Dwarkanath, Associate Professor of the Division of Nutrition at St. John’s Research Institute, stated, “The study found that low-dose calcium supplementation was equally effective as high-dose supplementation in preventing preeclampsia.” In the Indian trial, the incidence of preeclampsia was 3.0% for women taking 500 mg/day and 3.6% for those taking 1,500 mg/day. In Tanzania, the incidence was 3.0% and 2.7%, respectively.
While the study revealed varied results in preterm birth rates between trials, pooling data from both trials showed no significant difference in the effect of low-dose versus high-dose supplementation on preterm birth. This finding is crucial, as preterm birth is a leading cause of child mortality worldwide.
Funded by the Bill and Melinda Gates Foundation in collaboration with the Harvard TH Chan School of Public Health, the study emphasizes the potential cost-effectiveness and ease of compliance associated with a lower calcium dose.
Prof. Anura Kurpad, Professor of Physiology at St. John’s Medical College, highlighted the importance of reducing the dose of calcium to improve compliance, particularly in populations with low calcium intake.
“The striking findings of this large-scale non-inferiority trial, showing no difference on risk-reduction of preeclampsia between daily doses of 500 and 1,500 mg of calcium, is both cost-effective and easy to comply with,” said Dr. Dwarkanath.
The study’s results could inform policy decisions to minimize the incidence of preeclampsia and preterm birth in pregnancies globally, offering a simpler and more accessible approach to calcium supplementation for expectant mothers.
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