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Calcium Supplements Reduce Pregnancy Complications
GENEVA, March 10 -
Calcium supplements failed to prevent preeclampsia in healthy
pregnant women but reduced its more serious complications -- maternal morbidity
and neonatal mortality.
So determined a multicenter double-blind trial of 8,325 normotensive
nulliparous women, sponsored by the World Health Organization, that was reported
in the March 10 issue of the American Journal of Obstetrics and Gynecology.
Half the women were randomized to a calcium supplement of 1.5 g a day
throughout pregnancy while half received a placebo. The women, from populations
with low dietary calcium (less than 600 mg/d), were recruited from
antenatal-care clinics ranging from Argentina to Vietnam.
The primary endpoint, reducing preeclampsia, proved elusive. Calcium
supplementation was associated with a non-statistically significant small
reduction in preeclampsia (4.1% vs. 4.5%), said José Villar, M.D., of the WHO
here and colleagues.
However, other endpoints, though secondary, were promising. Dr. Villar
reported that the rates for 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.
Supplementation also brought about significant reductions in the most serious
complication of preeclampsia. Overall, the researchers wrote, there was a 25%
reduction in severe preeclamptic complications (risk ratio 0.76; 95% CI,
0.66-0.89). This is further reflected in the reduction in the index for severe
maternal morbidity and mortality (risk ratio 0.80; 95% CI 0.70-0.9) and,
finally, in a decrease in neonatal mortality (risk ratio 0.70; 95% CI,
0.56-0.88).
The causes of neonatal death for which calcium's benefits were most evident
were perinatal asphyxia, preterm delivery, and neonatal infection.
In addition, for a subgroup of mothers ages 20 and younger, supplementation
tended to reduce preterm and early preterm (less than 32 weeks) delivery (risk
ratio, 0.82; 95% CI, 067-1.01; risk ratio, 0.64; 95% CI, 0.42-0.98,
respectively). These young women, the researchers said, are known for poor
dietary habits and high calcium requirements.
In conclusion, Dr. Villar said that although calcium supplementation did not
lead to a statistically significant decrease in the overall rate of preeclampsia,
"treatment significantly reduced the risk of its more serious complications,
which included maternal and neonatal morbidity and death and preterm delivery,
the latter among young women."
Primary source: American Journal of Obstetrics
and Gynecology 2006:194,639-649
Source reference:
Villar, José, et al "World Health Organization randomized trial of calcium
supplementation among low calcium intake women"
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