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Randomized Controlled Trial
. 2006 Mar;194(3):639-49.
doi: 10.1016/j.ajog.2006.01.068.

World Health Organization randomized trial of calcium supplementation among low calcium intake pregnant women

José Villar  1 , Hany Abdel-Aleem, Mario Merialdi, Matthews Mathai, Mohamed M Ali, Nelly Zavaleta, Manorama Purwar, Justus Hofmeyr, Thi Nhu Ngoc Nguyen, Liana Campódonico, Sihem Landoulsi, Guillermo Carroli, Marshall Lindheimer; World Health Organization Calcium Supplementation for the Prevention of Preeclampsia Trial Group
Affiliations
Randomized Controlled Trial

World Health Organization randomized trial of calcium supplementation among low calcium intake pregnant women

José Villar et al. Am J Obstet Gynecol. 2006 Mar.

Abstract

Objective: The purpose of this trial was to determine whether calcium supplementation of pregnant women with low calcium intake reduces preeclampsia and preterm delivery.

Study design: Randomized placebo-controlled, double-blinded trial in nulliparous normotensive women from populations with dietary calcium < 600 mg/d. Women who were recruited before gestational week 20 received supplements (1.5 g calcium/d or placebo) throughout pregnancy. Primary outcomes were preeclampsia and preterm delivery; secondary outcomes focused on severe morbidity and maternal and neonatal mortality rates.

Results: The groups comprised 8325 women who were assigned randomly. Both groups had similar gestational ages, demographic characteristics, and blood pressure levels at entry. Compliance were both 85% and follow-up losses (calcium, 3.4%; placebo, 3.7%). Calcium supplementation was associated with a non-statistically significant small reduction in preeclampsia (4.1% vs 4.5%) that was evident by 35 weeks of gestation (1.2% vs 2.8%; P = .04). Eclampsia (risk ratio, 0.68: 95% CI, 0.48-0.97) and severe gestational hypertension (risk ratio, 0.71; 95% CI, 0.61-0.82) were significantly lower in the calcium group. Overall, there was a reduction in the severe preeclamptic complications index (risk ratio, 0.76; 95% CI, 0.66-0.89; life-table analysis, log rank test; P = .04). The severe maternal morbidity and mortality index was also reduced in the supplementation group (risk ratio, 0.80; 95% CI, 0.70-0.91). Preterm delivery (the neonatal primary outcome) and early preterm delivery tended to be reduced among women who were < or = 20 years of age (risk ratio, 0.82; 95% CI, 0.67-1.01; risk ratio, 0.64; 95% CI, 0.42-0.98, respectively). The neonatal mortality rate was lower (risk ratio, 0.70; 95% CI, 0.56-0.88) in the calcium group.

Conclusion: A 1.5-g calcium/day supplement did not prevent preeclampsia but did reduce its severity, maternal morbidity, and neonatal mortality, albeit these were secondary outcomes.

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