World Health Organization randomized trial of calcium supplementation among low calcium intake pregnant women.
OBJECTIVE
The purpose of this trial was to determine whether calcium supplementation of pregnant women with low calcium intake reduces preeclampsia and preterm delivery.


METHODS
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.


CONCLUSIONS
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.
Villar
José
J
Development Programme/United Nations Population Fund/World Health Organization/World Bank Special Programme of Research, Department of Reproductive Health and Research, World Health Organization, Geneva, Switzerland. villarj@who.int
Abdel-Aleem
Hany
H
Merialdi
Mario
M
Mathai
Matthews
M
Ali
Mohamed M
MM
Zavaleta
Nelly
N
Purwar
Manorama
M
Hofmeyr
Justus
J
Nguyen
Thi Nhu Ngoc
TN
Campódonico
Liana
L
Landoulsi
Sihem
S
Carroli
Guillermo
G
Lindheimer
Marshall
M
D000328:Adult; D002118:Calcium / Q000172:deficiency*; D002136:Calcium, Dietary / Q000627:therapeutic use*; D019587:Dietary Supplements; D004311:Double-Blind Method; D005260:Female; D006801:Humans; D007752:Obstetric Labor, Premature / Q000453:epidemiology / Q000209:etiology / Q000517:prevention & control*; D011225:Pre-Eclampsia / Q000453:epidemiology / Q000209:etiology / Q000517:prevention & control*; D011247:Pregnancy; D014944:World Health Organization
D002136:Calcium, Dietary; D002118:Calcium