Low-dose calcium in pregnancy (Tanzania)
Trial question
Is low-dose calcium supplementation noninferior to high-dose calcium supplementation in pregnant women?
Study design
Multi-center
Double blinded
RCT
Population
11000 female patients.
Inclusion criteria: adult nulliparous pregnant women.
Key exclusion criteria: history, signs, or symptoms of nephrolithiasis; history of parathyroid disorder or thyroidectomy; disease for which digoxin, phenytoin, or tetracycline is indicated.
Interventions
N=5503 low-dose calcium (at a daily dose of 500 mg).
N=5497 high-dose calcium (at a daily dose of 1,500 mg).
Primary outcome
Preeclampsia rates
3%
2.7%
3.0 %
2.3 %
1.5 %
0.8 %
0.0 %
Low-dose
calcium
High-dose
calcium
Difference not exceeding
non-inferiority
margin ✓
Difference not exceeding non-inferiority margin in preeclampsia rates (3% vs. 2.7%; RR 1.1, 95% CI 0.88 to 1.36).
Secondary outcomes
No significant difference in preterm birth (10.4% vs. 9.7%; RR 1.07, 95% CI 0.95 to 1.21).
No significant difference in gestational hypertension (4.1% vs. 4%; RR 1.02, 95% CI 0.85 to 1.22).
No significant difference in preeclampsia with severe features (1.8% vs. 1.7%; RR 1.06, 95% CI 0.8 to 1.4).
Safety outcomes
No significant difference in maternal hospitalization.
Conclusion
In adult nulliparous pregnant women, low-dose calcium was noninferior to high-dose calcium with respect to preeclampsia rates.
Reference
Pratibha Dwarkanath, Alfa Muhihi, Christopher R Sudfeld et al. Two Randomized Trials of Low-Dose Calcium Supplementation in Pregnancy. N Engl J Med. 2024 Jan 11;390(2):143-153.
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